Intervertebral implant and bone graft inserter

ABSTRACT

An adjustable spinal fusion intervertebral implant is provided that can comprise upper and lower body portions, and proximal and distal wedges. An actuator shaft disposed intermediate the upper and lower body portions can be actuated to cause proximal and distal wedges to converge towards each other. The implant comprises one or more channels that interact with a bone graft inserter to direct the flow of material through the implant. The bone graft inserter and methods of use are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims a priority benefit to U.S. ProvisionalApplication No. 62/241011, filed Oct. 13, 2015. The entire disclosure ofU.S. Provisional Application No. 62/241011, filed Oct. 13, 2015 ishereby incorporated by reference in its entirety and should beconsidered a part of this specification.

BACKGROUND

Field

The present invention relates to medical devices and, more particularly,to an intervertebral implant and a bone graft inserter.

Description of the Related Art

The human spine is a flexible weight bearing column formed from aplurality of bones called vertebrae. There are thirty three vertebrae,which can be grouped into one of five regions (cervical, thoracic,lumbar, sacral, and coccygeal). Moving down the spine, there aregenerally seven cervical vertebra, twelve thoracic vertebra, five lumbarvertebra, five sacral vertebra, and four coccygeal vertebra. Thevertebra of the cervical, thoracic, and lumbar regions of the spine aretypically separate throughout the life of an individual. In contrast,the vertebra of the sacral and coccygeal regions in an adult are fusedto form two bones, the five sacral vertebra which form the sacrum andthe four coccygeal vertebra which form the coccyx.

In general, each vertebra contains an anterior, solid segment or bodyand a posterior segment or arch. The arch is generally formed of twopedicles and two laminae, supporting seven processes—four articular, twotransverse, and one spinous. There are exceptions to these generalcharacteristics of a vertebra. For example, the first cervical vertebra(atlas vertebra) has neither a body nor spinous process. In addition,the second cervical vertebra (axis vertebra) has an odontoid process,which is a strong, prominent process, shaped like a tooth, risingperpendicularly from the upper surface of the body of the axis vertebra.Further details regarding the construction of the spine may be found insuch common references as Gray's Anatomy, Crown Publishers, Inc., 1977,pp. 33-54, which is herein incorporated by reference.

The human vertebrae and associated connective elements are subjected toa variety of diseases and conditions which cause pain and disability.Among these diseases and conditions are spondylosis, spondylolisthesis,vertebral instability, spinal stenosis and degenerated, herniated, ordegenerated and herniated intervertebral discs. Additionally, thevertebrae and associated connective elements are subject to injuries,including fractures and torn ligaments and surgical manipulations,including laminectomies.

The pain and disability related to the diseases and conditions oftenresult from the displacement of all or part of a vertebra from theremainder of the vertebral column. Over the past two decades, a varietyof methods have been developed to restore the displaced vertebra totheir normal position and to fix them within the vertebral column.Spinal fusion is one such method. In spinal fusion, one or more of thevertebra of the spine are united together (“fused”) so that motion nolonger occurs between them. Thus, spinal fusion is the process by whichthe damaged disc is replaced and the spacing between the vertebrae isrestored, thereby eliminating the instability and removing the pressureon neurological elements that cause pain.

Spinal fusion can be accomplished by providing an intervertebral implantbetween adjacent vertebrae to recreate the natural intervertebralspacing between adjacent vertebrae. Once the implant is inserted intothe intervertebral space, osteogenic substances, such as autogenous bonegraft or bone allograft, can be strategically implanted adjacent theimplant to prompt bone ingrowth in the intervertebral space. The boneingrowth promotes long-term fixation of the adjacent vertebrae. Variousposterior fixation devices (e.g., fixation rods, screws etc.) can alsobe utilize to provide additional stabilization during the fusionprocess.

Recently, intervertebral implants have been developed that allow thesurgeon to adjust the height of the intervertebral implant. Thisprovides an ability to intra-operatively tailor the intervertebralimplant height to match the natural spacing between the vertebrae. Thisreduces the number of sizes that the hospital must keep on hand to matchthe variable anatomy of the patients.

In many of these adjustable intervertebral implants, the height of theintervertebral implant is adjusted by expanding an actuation mechanismthrough rotation of a member of the actuation mechanism. In someintervertebral implants, the actuation mechanism is a screw or threadedportion that is rotated in order to cause opposing plates of the implantto move apart. In other implants, the actuation mechanism is a helicalbody that is counter-rotated to cause the body to increase in diameterand expand thereby.

Furthermore, notwithstanding the variety of efforts in the prior artdescribed above, these intervertebral implants and techniques areassociated with another disadvantage. In particular, these techniquestypically involve an open surgical procedure, which results higher cost,lengthy in-patient hospital stays and the pain associated with openprocedures.

Therefore, there remains a need in the art for an improvedintervertebral implant. Preferably, the implant is implantable through aminimally invasive procedure. Further, such devices are preferably easyto implant and deploy in such a narrow space and opening while providingadjustability and responsiveness to the clinician.

SUMMARY

Accordingly, one embodiment can comprise an assembly that includes anexpandable implant comprising upper and lower body portions An actuatorshaft can be received between the upper and lower body portions. Aproximal wedge member and a distal wedge member can be coupled to theactuator shaft. A channel can extend from the proximal wedge memberthrough the expandable implant. Rotation of the actuator shaft can causemovement of one or more of the proximal wedge member and the distalwedge member. A tool can be configured to engage a portion of theexpandable implant for placement within the intervertebral space. Thetool can include a central lumen in communication with the channelconfigured to direct material from the tool toward the channel. The toolcan remain in place during insertion of the implant, expansion of theimplant, and movement of the material toward the channel

One embodiment can include a method that comprises coupling an implantwith a tool positioning the implant between adjacent vertebrae with thetool, the implant comprising upper and lower body portions, an actuatorshaft received between the upper and lower body portions, a proximalwedge member and a distal wedge member coupled to the actuator shaft,and a channel extending from the proximal wedge member through theexpandable implant, rotating the actuator shaft to expand the implantwhile the implant is coupled to the tool, directing material from thetool toward the implant while the implant is coupled to the tool, anddecoupling the implant with the tool.

In accordance with another embodiment, an assembly can include anexpandable implant comprising upper and lower body portions configuredto be moved apart to expand the expandable implant. A channel can extendat least from an outside surface of the expandable implant to an insidesurface of the expandable implant. A tool can be configured to engagethe expandable implant for placement within the intervertebral space,the tool comprising a central lumen in communication with the channelconfigured to direct material from the tool toward the channel andtoward the inside surface of the expandable implant The tool can remainin place during insertion of the implant, expansion of the implant, andmovement of the material toward the channel.

In accordance with another embodiment, a method can include coupling animplant with a tool, positioning the implant between adjacent vertebraewith the tool expanding the implant while the implant is coupled withthe tool, directing material from the tool toward a channel in theimplant while the implant is coupled to the tool; and decoupling theimplant with the tool.

In accordance with yet another embodiment, a method of implanting aimplant can include the steps of positioning the implant between twovertebral bodies and rotating a screw mechanism of the implant to causeproximal and distal wedge members to converge toward each other andengage respective ones of proximal and distal surfaces of upper andlower body portions of the implant to separate the upper and lower bodyportions to cause the implant to expand.

In accordance certain embodiments, an adjustable spinal fusionintervertebral implant is provided that comprises upper and lower bodyportions, proximal and distal wedge members, and a pin.

The upper and lower body portions can each have proximal and distalsurfaces at proximal and distal ends thereof. The proximal and distalsurfaces of the upper and lower body portions can generally face eachother. The proximal surfaces of the respective ones of the upper andlower body portions can each define a proximal slot therein. The distalsurfaces of the respective ones of the upper and lower body portions caneach define a distal slot therein.

The proximal wedge member can be disposed at the proximal ends of therespective ones of the upper and lower body portions. The proximal wedgemember can comprise upper and lower guide members extending at leastpartially into the respective ones of the proximal slots of the upperand lower body portions with at least a portion of the proximal wedgemember contacting the proximal surfaces of the upper and lower bodyportions. The distal wedge member can be disposed at the distal ends ofthe respective ones of the upper and lower body portions. The distalwedge member can comprise upper and lower guide members extending atleast partially into the respective ones of the distal slots of theupper and lower body portions with at least a portion of the distalwedge member contacting the distal surfaces of the upper and lower bodyportions.

The actuator shaft can be received between the upper and lower bodyportions. The actuator shaft can extend intermediate the distal andproximal wedge members, wherein rotation of the actuator shaft causesthe distal and proximal wedge members to be drawn together such thatlongitudinal movement of the distal wedge member against the distalsurfaces and the longitudinal movement of the proximal wedge memberagainst the proximal surfaces causes separation of the upper and lowerbody portions.

In such an embodiment, the upper body portion can further comprise apair of downwardly extending side members and the lower body portionfurther comprises a pair of upwardly extending side members. The sidemembers of the upper body portion can engage the side members of thelower body portion to facilitate linear translational movement of theupper body portion relative to the lower body portion. The side membersof the upper body portion can each comprise a slot and the side membersof the lower body portion each comprise a guide member. The guidemembers of the side members of the lower body portion can each bereceived into the slots of the side members of the upper body portion.

The implant can be configured wherein the proximal and distal surfacesof the upper and lower body portions are sloped. The slots of theproximal and distal surfaces of the upper and lower body portions canalso be sloped. Further, the slots of the proximal and distal surfacesof the upper and lower body portions can be generally parallel to therespective proximal and distal surfaces of the upper and lower bodyportions. In other embodiments, the slots of the proximal and distalsurfaces of the upper and lower body portions can be generallydove-tailed. The guide members of the proximal and distal wedge memberscan also be generally dovetailed. In other embodiments, the upper andlower body portions can comprise generally arcuate respective upper andlower exterior engagement surfaces.

The proximal wedge member can comprise an anti-rotational element. Theanti-rotational engagement can be configured to be engaged by an implanttool for preventing rotation of the implant when the actuator shaft isrotated relative to the implant. The anti-rotational element cancomprise a pair of apertures extending into the proximal wedge member.

In yet another embodiment, an implantation tool is provided forimplanting an expandable intervertebral implant. The tool can comprise ahandle section, a distal engagement section, and an anti-rotationalengagement member. The handle section can comprise a fixed section andfirst and second rotatable members. The distal engagement section cancomprise a fixed portion and first and second rotatable portions beingoperatively coupled to the respective ones of the first and secondrotatable members. The first rotatable portion can comprise a distalattachment element. The distal engagement element can be operative to beremovably attached to a distal end of at least a portion of the implant.The second rotatable portion can comprise a distal engagement memberbeing configured to engage a proximal end of an actuator shaft of theimplant for rotating the actuator shaft to thereby and expanding theimplant from an unexpanded state to and expanded state. Theanti-rotational engagement member can be used to engage ananti-rotational element of the implant.

In some embodiments, the first and second rotatable members of the toolcan be coaxially aligned. Further, the first and second rotatableportions can be coaxially aligned. The first and second rotatableportions can be tubular, and the first rotatable portion can be disposedinternally to the second rotatable portion. The fixed portion of thedistal engagement section can be tubular and the first and secondrotatable portions can be disposed internally to the fixed portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an intervertebral implant in an unexpandedstate while positioned intermediate adjacent vertebrae, according to anembodiment.

FIG. 2 is a side view of the intervertebral implant shown in FIG. 1 inan expanded state.

FIG. 3 is a perspective view of the intervertebral implant shown in FIG.1 in an unexpanded state.

FIG. 4 is a perspective view of the intervertebral implant shown in FIG.3 in an expanded state.

FIG. 5 is a side cross sectional view of the intervertebral implantshown in FIG. 3 in an unexpanded state.

FIG. 6 is a side cross-sectional view of the intervertebral implantshown in FIG. 5 in an expanded state.

FIG. 7 is a side cross-sectional view of the intervertebral implantshown in FIG. 5 in an expanded state and wherein a portion of anactuator shaft has been removed.

FIG. 8 is a side cross sectional view of another embodiment of theactuator shaft of the intervertebral implant shown in FIG. 3, whereinthe actuator shaft has an outer sleeve member and an inner sleevemember.

FIG. 9A is a side perspective view of a portion of a modified embodimentof the outer sleeve member.

FIG. 9B is an enlarged longitudinal cross-sectional view of a modifiedembodiment of the outer sleeve member with the portion shown in FIG. 9A.

FIG. 9C is a perspective view of another embodiment of an outer sleevemember.

FIGS. 9D and 9E are enlarged views of a portion of one embodiment of anouter sleeve member.

FIG. 9F is a front view of the outer sleeve member shown in FIG. 9C.

FIG. 10A is a side cross sectional view of another embodiment of anintervertebral implant.

FIG. 10B is an enlarged view of the section 10B shown in FIG. 10A.

FIG. 11 is a side cross-sectional view of another embodiment of anactuator shaft of the intervertebral implant shown in FIG. 10A.

FIG. 12 is a perspective view of the embodiment of the intervertebralimplant shown in FIG. 10A in an unexpanded state.

FIG. 13 is a perspective view of the embodiment of the intervertebralimplant shown in FIG. 10A in an expanded state.

FIG. 14A is a side view of another embodiment of the intervertebralimplant wherein the upper and lower body portions have generally slantedconfigurations.

FIG. 14B is a top view of another embodiment of the intervertebralimplant wherein the upper and lower body portions have semicircularupper and lower faces.

FIG. 14C is a top view of another embodiment of the intervertebralimplant wherein the upper and lower body portions have generally squareupper and lower faces.

FIG. 14D is a top view illustrating an embodiment of an application ofthe intervertebral implant utilizing a plurality of intervertebralimplants disposed in an intervertebral space to support adjacentvertebrae.

FIG. 15 is a side cross-sectional view of another embodiment of theintervertebral implant wherein rotational movement can be utilized toexpand the implant.

FIG. 16A is a perspective view of another embodiment of anintervertebral implant in an unexpanded state.

FIG. 16B is a perspective view of the intervertebral implant shown inFIG. 16A wherein the implant is in an expanded state.

FIG. 17 is a bottom view of the intervertebral implant shown in FIG.16A.

FIG. 18 is a side view of the intervertebral implant shown in FIG. 16B.

FIG. 19 is a front cross-sectional view of the intervertebral implantshown in FIG. 16B taken along lines 19-19.

FIG. 20A is a bottom perspective view of a lower body portion of theintervertebral implant shown in FIG. 16A.

FIG. 20B is a top perspective view of the lower body portion of theintervertebral implant shown in FIG. 16A.

FIG. 21A is a bottom perspective view of an upper body portion of theintervertebral implant shown in FIG. 16A.

FIG. 21B is a top perspective view of the upper body portion of theintervertebral implant shown in FIG. 16A.

FIG. 22 is a perspective view of an actuator shaft of the intervertebralimplant shown in FIG. 16A.

FIG. 23A is a front perspective view of a proximal wedge member of theintervertebral implant shown in FIG. 16A.

FIG. 23B is a rear perspective view of the proximal wedge member of theintervertebral implant shown in FIG. 16A.

FIG. 24A is a front perspective view of a distal wedge member of theintervertebral implant shown in FIG. 16A.

FIG. 24B is a rear perspective view of the distal wedge member of theintervertebral implant shown in FIG. 16A.

FIG. 25 is a perspective view of a deployment tool according to anembodiment.

FIG. 26 is a side cross-sectional view of the deployment tool shown inFIG. 25 wherein an expandable implant is attached to a distal endthereof

FIG. 27 is a perspective view of another embodiment of an implant.

FIG. 28 is a cross-sectional view of a bone graft inserter of accordingto an embodiment.

FIG. 29 is a cross-sectional view of the bone graft inserter shown inFIG. 28 with the bone graft advanced into the implant.

FIG. 30 is a perspective cross-sectional view of the bone graft insertershown in FIG. 28.

FIG. 31 is a perspective cross-sectional view of the bone graft insertershown in FIG. 28 with the bone graft advanced into the implant.

DETAILED DESCRIPTION

In accordance with certain embodiments disclosed herein, an improvedintervertebral implant is provided that allows the clinician to insertthe intervertebral implant through a minimally invasive procedure. Forexample, in one embodiment, one or more intervertebral implants can beinserted percutaneously to reduce trauma to the patient and therebyenhance recovery and improve overall results of the surgery.

For example, in one embodiment, an intervertebral implant includes aplurality of body sections that are selectively separable and expandableupon contraction of a centrally disposed actuator. The actuator can beutilized to contract against faces of the body sections to cause theexpansion thereof. The implant can also be configured such that theactuator provides for both the expansion and contraction of the bodysections. The actuator can comprise an interaction between the bodysections and another element, an action performed by another element, ora combination of interactions between various elements of the implantand its body sections. Further, the implant can be configured to alloweither rough or fine incremental adjustments in the expansion of theimplant.

The embodiments disclosed herein are discussed in the context of anintervertebral implant and spinal fusion because of the applicabilityand usefulness in such a field. As such, various embodiments can be usedto properly space adjacent vertebrae in situations where a disc hasruptured or otherwise been damaged. As also disclosed herein,embodiments can also be used as vertebral body replacements. Thus,“adjacent” vertebrae can include those originally separated only by adisc or those that are separated by intermediate vertebra and discs.Such embodiments can therefore tend to recreate proper disc height andspinal curvature as required in order to restore normal anatomicallocations and distances. However, it is contemplated that the teachingsand embodiments disclosed herein can be beneficially implemented in avariety of other operational settings, for spinal surgery and otherwise.

For example, the implant disclosed herein can also be used as avertebral body replacement. In such a use, the implant could be used asa replacement for a lumbar vertebra, such as one of the L1-L5 vertebrae.Thus, the implant could be appropriately sized and configured to be usedintermediate adjacent vertebrae, or to entirely replace a damagedvertebra.

It is contemplated that the implant can be used as an interbody orintervertebral device or can be used to replace a vertebral bodyentirely. The implant can also be used in veterbal body compressionfractures. Further, the implant can be used as a tool to expand anintervertebral space or bone in order to fill the space or bone with acement; in such cases, the implant can be removed or left in once thecement is placed. Furthermore, the implant can also be used as a tool topredilate disc space. In some embodiments, the implant can be removedonce the disc space is dilated, and a different implant (expandable ornon-expandable) can then be implanted in the dilated disc space.Finally, the implant can also be introduced into the disc spaceanteriorly in an anterior lumbar interbody fusion (ALIF) procedure,posterior in an posterior lumbar interbody fusion (PILF) or posteriallateral interbody fusion, from extreme lateral position in an extremelateral interbody fusion procedure , and transforaminal lumbar interbodyfusion (TLIF), to name a few. Although the implant is primarilydescribed herein as being used to expand in a vertical direction, it canalso be implanted to expand in a horizontal direction in order toincrease stability and/or increase surface area between adjacentvertebral bodies.

Additionally, the implant can comprise one or more height changemechanisms to facilitate expansion of the implant. For example, theimplant can use a classic wedge system, a parallel bar and linkagesystem, a jack system, a pair of inclined planes, a screw jack system, acam system, a balloon and bellows system, a hydraulic or pneumaticsystem, a longitudinal deformation/crush system (in which longitudinalcontraction creates vertical expansion), or a stacking system, to name afew. Furthermore, the implant can comprise one or more height retentionmechanisms. For example, the implant can use a pin ratchet system, awedge ratchet system, a lead screw system with left or right-handthreads, or a lead screw system with left and right-hand threads, toname a few.

Therefore, it is contemplated that a number of advantages can berealized utilizing various embodiments disclosed herein. For example, aswill be apparent from the disclosure, no external distraction of thespine is necessary. Further, no distraction device is required in orderto install various embodiments disclosed herein. In this regard,embodiments of the implant can enable sufficient distraction of adjacentvertebra in order to properly restore disc height or to use the implantas a vertebral body replacement. Thus, normal anatomical locations,positions, and distances can be restored and preserved utilizing many ofthe embodiments disclosed herein.

Referring to FIG. 1, there is illustrated a side view of an embodimentof a intervertebral implant 10 in an unexpanded state while positionedgenerally between adjacent vertebrae of the lumbar portion of the spine12. FIG. 2 illustrates the intervertebral implant 10 in an expandedstate, thereby supporting the vertebrae in a desired orientation andspacing in preparation for spinal fusion. As is known in the art, spinalfusion is the process by which the adjacent vertebrae of the spine areunited together (“fused”) so that motion no longer occurs between thevertebrae. Thus, the intervertebral implant 10 can be used to providethe proper spacing two vertebrae to each other pending the healing of afusion. See also U.S. Patent Publication No. 2004/0127906, filed Jul.18, 2003, application Ser. No. 10/623,193, the entirety of thedisclosure of which is hereby incorporated by reference.

According to an embodiment, the implant can be installed in an operationthat generally entails the following procedures. The damaged disc orvertebra can be decompressed, such as by distracting. The subjectportion (or entire) disc or vertebra can then be removed. The adjacentvertebrae can be prepared by scraping the exposed adjacent portion orplates thereof (typically to facilitate bleeding and circulation in thearea). Typically, most of the nucleus of the disc is removed and theannulus of the disc is thinned out. Although individual circumstancesmay vary, it may be unusual to remove all of the annulus or to perform acomplete diskectomy. The implant can then be installed. In someembodiments, distraction of the disc may not be a separate step fromplacement of the implant; thus, distraction can be accomplished and canoccur during placement of the implant. Finally, after implantation ofthe implant, osteogenic substances, such as autogenous bone graft, boneallograft, autograft foam, or bone morphogenic protein (BMP) can bestrategically implanted adjacent the implant to prompt bone ingrowth inthe intervertebral space. In this regard, as the implant is expanded,the spaces within the implant can be backfilled; otherwise, the implantcan be prepacked with biologics.

The intervertebral implant is often used in combination with posteriorand/or anterior fixation devices (e.g., rods, plates, screws, etc. thatspan two or more vertebrae) to limit movement during the fusion process.U.S. Patent Publication No. 2004/0127906 discloses a particularlyadvantageous posterior fixation device and method which secures twoadjacent vertebra to each other in a trans-laminar, trans-facet orfacet-pedicle (e.g., the Boucher technique) application using fixationscrews.

It should also be appreciated that in FIGS. 1 and 2 only oneintervertebral implant 10 is shown positioned between the vertebrae 12.However, as will be discussed in more detail below, it is anticipatedthat two, three or more implants 10 can be inserted into the spacebetween the vertebrae. Further, other devices, such as bone screws, canbe used on the vertebrae as desired. For example, in a spinal fusionprocedure, it is contemplated that one or more implants 10 can be usedin conjunction with one or more bone screws and/or dynamic stabilizationdevices, such as those disclosed in the above-mentioned U.S. PatentPublication No. 2004/0127906, filed Jul. 18, 2003, application Ser. No.10/623,193.

In another embodiment of use, the implant 10 can be used in combinationwith a dynamic stabilization devices such as those disclosed in U.S.Patent Publication No. 2006-0122609, filed Feb. 11, 2005, applicationSer. No. 11/056,991; U.S. Patent Publication No. 2005/0033289, filed onMay 6, 2004, now U.S. Pat. No. 6,951,561; U.S. Provisional PatentApplication No. 60/942,998, filed on Jun. 8, 2007; U.S. ProvisionalApplication No. 60/397,588 filed Jul. 19, 2002; U.S. ProvisionalApplication No. 60/424,055, filed Nov. 5, 2002; Ser. No. 10/623,193;U.S. Provisional Application No. 60/397,588 filed Jul. 19, 2002 andProvisional Application 60/424,055 filed Nov. 5, 2002; the entireties ofthe disclosures of which are hereby incorporated by reference. In thismanner, the implant 10 can be used to maintain height between vertebralbodies while the dynamic stabilization device provides limits in one ormore degrees of movement.

The embodiment of the intervertebral implant 10 shown FIGS. 1 and 2 willnow be described in more detail with reference FIGS. 3 and 4. FIG. 3illustrates a perspective view the intervertebral implant 10 in anunexpanded state while FIG. 4 illustrates the intervertebral implant 10in an expanded state. The intervertebral implant 10 can comprise anupper body portion 14 and a lower body portion 16. The upper and lowerbody portions 14, 16 can each have a proximally facing surface 18, 20disposed at respective proximal ends 22, 24 thereof and generally facingeach other. As will be explained below, the proximally facing surfaces18, 20 can be inclined or otherwise curved with respect to thelongitudinal axis of the body portions 14, 16.

In the illustrated embodiment, the upper and lower body portions 14, 16are illustrated as being configured substantially as parallel plate likestructures. As will be explained below, the upper and lower bodyportions 14, 16 can be variously configured and designed, such as beinggenerally ovular, wedge-shaped, and other shapes. For example, insteadof including smooth exterior surfaces, as shown, the upper and lowerbody portions 14, 16 can be configured to include a surface texture,such as one or more external teeth, in order to ensure that theintervertebral implant 10 is maintained in a given lateral position onceexpanded intermediate the adjacent vertebrae of the spine 12. Other suchmodifications can be implemented in embodiments disclosed herein, andmay be readily understood by one of skill in the art.

The intervertebral implant 10 can further comprise an actuator shaft 30that can be sized and configured to be received between the upper andlower body portions 14, 16. As described herein with respect to variousembodiments, the actuator shaft 30 can be utilized not only to move theintervertebral implant 10 from the unexpanded to the expanded state, butalso to maintain expansion of the intervertebral implant 10. Theactuator shaft 30 can be utilized in several embodiments to providenumerous advantages, such as facilitating precise placement, access, andrapid deployment of the intervertebral implant 10.

As shown in FIGS. 5 and 6, the actuator shaft 30 can comprise an innermember 32 and an outer sleeve member 34. In accordance with anembodiment, the outer sleeve member 34 can be adapted to be translatablerelative to the inner member 32 such that the distance between thedistal end of the inner member 32 and the proximal end of the outermember 34 can be reduced or shortened. The inner member 32 can have adistal end 36, a proximal end 38, and at least one retention structure40 disposed therebetween. The outer sleeve member 32 can also have aproximal end 42 and at least one complementary retention structure 44.

In general, the retention structures 40, 44 between the inner member 32and the outer member 34 can be configured such that facilitate selectiverelative movement of the proximal end 42 of the outer sleeve member 34with respect to the distal end 36 of the inner member 32. Whilepermitting such selective relative movement, the structures 40, 44 arepreferably configured to resist movement once the distance between theproximal end 42 of the outer sleeve member 34 with respect to the distalend 36 of the inner member 32 is set. As will be described below, theretention structures 40, 44 can comprise any of a variety threads orscrew-like structures, ridges, ramps, and/or ratchet type mechanismswhich those of skill in the art will recognize provide such movement.

In some embodiments, the movement of proximal end 42 of the outer sleevemember 34, which may be in a direction distal to the clinician, can beaccomplished without rotation of the actuator shaft 30, or any portionthereof. Thus, some embodiments provide that the actuator shaft 30 canbe advantageously moved to the engaged position using only substantiallylongitudinal movement along an axis of the actuator shaft 30. It iscontemplated that this axial translation of the outer sleeve member 34can aid the clinician and eliminate cumbersome movements such asrotation, clamping, or otherwise. In this regard, the clinician caninsert, place, and deploy the intervertebral implant 10 percutaneously,reducing the size of any incision in the patient, and thereby improvingrecovery time, scarring, and the like. These, and other benefits aredisclosed herein.

In accordance with another embodiment, the proximal end 38 of theactuator shaft 30 can also be provided with a structure 48 forpermitting releasable engagement with an installation or a removal tool50. The actuator shaft 30 can therefore be moved as required and thetool 50 can later be removed in order to eliminate any substantialprotrusions from the intervertebral implant 10. This feature can allowthe intervertebral implant 10 to have a discreet profile once implantedinto the patient and thereby facilitate healing and bone growth, whileproviding the clinician with optimal control and use of theintervertebral implant 10.

For example, as shown in FIG. 5, structure 48 comprises interactingthreads between the distal end of the tool 50 and the proximal end 38 ofthe inner member 32. In a modified embodiment, the structure 48 cancomprise any of a variety of fixation devices (e.g., hooks, latches,threads, etc.) as will be apparent to those of skill in the art. Theactuator shaft 30 can therefore be securely coupled to the tool 50during implantation of the intervertebral implant 10. Once disposed inthe intervertebral space, the clinician can grasp the tool 50 tomaintain the inner member 32 of the actuator shaft 30 at a constantposition while pushing the outer sleeve member 34 in the distaldirection and/or pull on the tool to proximally retract the inner member32 while maintaining the outer member 34 stationary. Thus, the cliniciancan effectuate movement of the actuator shaft 30 and/or apply a forcethe actuator shaft 30. As will be described further below, this movementcan thereby cause the intervertebral implant 10 to move from theunexpanded to the expanded state.

Alternatively, the tool 50 can be omitted and/or combined with theactuator shaft 30 such that the actuator shaft 30 includes a proximalportion that extends proximally in order to allow the clinician tomanipulate the actuator shaft 30 position, as described with respect tothe tool 50. In such an embodiment, the actuator shaft 30 can beprovided with a first break point to facilitate breaking a proximalportion of the actuator shaft 30 which projects proximally of theproximal end 42 of the outer sleeve member 34 following tensioning ofthe actuator shaft 30 and expansion of the intervertebral implant 10.The break point can comprise an annular recess or groove, which canprovide a designed failure point if lateral force is applied to theproximal portion while the remainder of the attachment system isrelatively securely fixed in the intervertebral space. At least a secondbreak point can also be provided, depending upon the axial range oftravel of the outer sleeve member 34 with respect to the inner member32. Other features and embodiments can be implemented as described inU.S. Pat. No. 6,951,561, the disclosure of which is hereby incorporatedby reference in its entirety.

The retention structures 40, 44 of the inner member 32 and the outersleeve member 34 can thus permit proximal movement of the inner member32 with respect to the outer sleeve member 34 but resist distal movementof the inner member 32 with respect to the outer sleeve member 34. Asthe outer sleeve member 34 moves in the distal direction, thecomplementary retention structures 44 can engage the retentionstructures 40 of the inner member 32 to allow advancement of the outersleeve member 34 in a distal direction with respect to inner member 32,but which resist proximal motion of outer sleeve member with respect toinner member 32. This can result in one-way or ratchet-type movement.Thus, in such an embodiment, at least one of the complementary retentionstructures 44 and the retention structures can comprise a plurality ofannular rings, ramps, or ratchet-type structures. As mentioned above,any of a variety of ratchet-type structures can be utilized.

The actuator shaft 30 can also be configured to include a noncircularcross section or to have a rotational link such as an axially-extendingspline on the inner member 32 for cooperating with a complementarykeyway on the outer sleeve member 34. In another embodiment, theretention structures 40, 44 can be provided on less than the entirecircumference of the inner member 32 or outer sleeve member 34, as willbe appreciated by those of skill in the art. Thus, ratchet structurescan be aligned in an axial strip such as at the bottom of an axiallyextending channel in the surface of the inner member 32. In this manner,the outer sleeve member 34 can be rotated to a first position to bypassthe retention structures 40, 44 during axial advancement and thenrotated to a second position to engage the retention structures 40, 44.

In accordance with another embodiment, the retention structures 40 ofthe inner member 32 can comprise a plurality of threads, adapted tocooperate with the complimentary retention structures 44 on the outersleeve member 34, which may be a complimentary plurality of threads. Insuch an embodiment, the outer sleeve member 34 can be distally advancedalong the inner member 32 by rotation of the outer sleeve member 34 withrespect to the inner member 32, thus causing expansion of theintervertebral implant 10. The outer sleeve member 34 can alsoadvantageously be removed from the inner member 32 by reverse rotation,such as to permit contraction of the intervertebral implant 10 to theunexpanded state in order to adjust the position thereof within theintervertebral space or to facilitate the removal of the intervertebralimplant 10 from the patient.

For such a purpose, the outer sleeve member 34 can be preferablyprovided with a gripping configuration, structure, or collar 52 (seee.g., FIG. 7) to permit a removal instrument to rotate the outer sleevemember 34 with respect to the inner member 32. For example, such aninstrument can be concentrically placed about the tool 50 and engage thecollar 52. Thus, while holding the tool 50 in a fixed position, theclinician can reverse rotate the instrument to move the outer sleevemember 34 in a proximal direction. Any of a variety of grippingconfigurations may be provided, such as one or more slots, flats, bores,or the like. In the illustrated embodiment, the collar 52 can beprovided with a polygonal, and in particular, a hexagonal circumference,as seen in FIGS. 7 and 8.

Various embodiments and/or additional or alternative components of theactuator shaft 30 and the retention structures 40, 44 can be found inU.S. Patent Publication 2004/0127906 (U.S. patent application Ser. No.10/623,193, filed Jul. 18, 2003) entitled “METHOD AND APPARATUS FORSPINAL FUSION”, which is hereby incorporated by reference. Additionalembodiments and/or alternative components of the actuator shaft 30 canbe found in U.S. Patent Application No. 60/794,171, filed on Apr. 21,2006, U.S. Pat. Nos. 6,951,561, 6,942,668, 6,908,465, and 6,890,333,which are also incorporated by reference. For example, as described inU.S. Pat. No. 6,951,561, the actuator shaft 30 can be configured withparticular spacing between the retention structures 40, 44; the actuatorshaft 30 dimensions, such as diameter and cross-section, can bevariously configured; and the actuator shaft 30 can be manufactured ofvarious types of materials.

FIGS. 9A and 9B illustrate a portion of a modified embodiment of anouter sleeve member and inner member that is similar to the embodimentsdescribed above. In this embodiment, the outer sleeve member preferablyincludes a recess 54 configured to receive an annular ring 55. In anembodiment, the annular ring 55 can be a split ring (i.e., having aleast one gap) and can be interposed between the inner member 32 and theproximal recess 54 of the outer sleeve member. In another embodiment,the ring 55 can be formed from an elastic material configured to ratchetover and engage with the inner member 32. In the split ring embodiment,the ring 55 comprises a tubular housing 56 that may be configured toengage with the inner member 32 and defines a gap or space 57. In oneembodiment, the gap 57 is defined by a pair of edges 58, 59. The edges58, 59 can be generally straight and parallel to each other. However,the edges 58, 59 can have any other suitable configuration andorientation.

For example, in one embodiment, the edges 58, 59 are curved and at anangle to each other. Although not illustrated, it should be appreciatedthat in modified embodiments, the ring 55 can be formed without a gap.When the ring 55 is positioned along the inner member 32, the ring 55preferably surrounds a substantial portion of the inner member 32. Thering 55 can be sized so that the ring 55 can flex or move radiallyoutwardly in response to an axial force so that the ring 55 can be movedrelative to the inner member 32. In one embodiment, the tubular housing56 includes at least one and in the illustrated embodiment four teeth orflanges 60, which are configured to engage the retention structures 40on the inner member 32. In the illustrated embodiment, the teeth orflanges include a first surface that generally faces the proximaldirection and is inclined with respect to the longitudinal axis of theouter sleeve member and a second surface that faces distal direction andlies generally perpendicular to the longitudinal axis of the outersleeve member. It is contemplated that the teeth or flanges 60 can haveany suitable configuration for engaging with the retention structures 40of the inner member 32.

As with the previous embodiment, the outer sleeve member can includesthe annular recess 54 in which the annular ring 55 may be positioned.The body 56 of the ring 55 can be sized to prevent substantial axialmovement between the ring 55 and the annular recess 54 (FIG. 9B) duringuse of the outer sleeve member. In one embodiment, the width of theannular recess 54 in the axial direction is slightly greater than thewidth of the annular ring 55 in the axial direction. This tolerancebetween the annular recess 54 and the annular ring 55 can inhibit, orprevent, oblique twisting of the annular ring 55 so that the body 56 ofthe ring 55 is generally parallel to the outer surface of the innermember 32.

Further, the recess 54 can be sized and dimensioned such that as theouter sleeve member is advanced distally over the inner member 32, theannular ring 55 can slide along the first surface and over thecomplementary retention structures 40 of the inner member 32. That is,the recess 54 can provide a space for the annular ring 55 to moveradially away from the inner member 32 as the outer sleeve member isadvanced distally. Of course, the annular ring 55 can be sized anddimensioned such that the ring 55 is biased inwardly to engage theretention structures 40 on the inner member 32. The bias of the annularring 55 can result in effective engagement between the flanges 60 andthe retention structures 40.

A distal portion 61 of the recess 54 can be sized and dimensioned suchthat after the outer sleeve member 53 is appropriately tensioned theannular ring 55 becomes wedged between the inner member 32 and an angledengagement surface of the distal portion 61. In this manner, proximalmovement of the outer sleeve member 53 can be prevented.

FIGS. 9C-9F illustrate another embodiment of an outer sleeve member 53′.In this embodiment, the outer sleeve member 53′ includes a recess 54configured to receive a split ring 55, as described above with referenceto FIGS. 9A and 9B. As will be explained in detail below, the outersleeve member 53′ can include an anti-rotation feature to limit orprevent rotation of the ring 55 within the outer sleeve member 53. Inlight of the disclosure herein, those of skill in the art will recognizevarious different configurations for limiting the rotation of the ring55. However, a particularly advantageous arrangement will be describedbelow with reference to the illustrated embodiment.

In the illustrated embodiment, the outer sleeve member 53′ has a tubularhousing 62 that can engage with the inner member 32 or the tool 50, asdescribed above. With reference to FIGS. 9D and 9F, the tubular housing62 can comprise one or more anti-rotational features 63 in the form of aplurality of flat sides that are configured to mate correspondinganti-rotational features 64 or flat sides of the inner member 32 of theactuator shaft 30. As shown in FIG. 9F, in the illustrated embodiment,the inner member 32 has three flat sides 64. Disposed between the flatsides 64 are the portions of the inner member 32 which include thecomplementary locking structures such as threads or ratchet likestructures as described above. The complementary locking structuresinteract with the ring 55 as described above to resist proximal movementof the outer sleeve member 53′ under normal use conditions whilepermitting distal movement of the outer sleeve member 53′ over the innermember 32.

As mentioned above, the ring 55 can be is positioned within the recess54. In the illustrated embodiment, the recess 54 and ring 55 arepositioned near to and proximal of the anti-rotational features 63.However, the ring 55 can be located at any suitable position along thetubular housing 62 such that the ring 55 can interact with the retentionfeatures of the inner member 32.

During operation, the ring 55 may rotate to a position such that the gap57 between the ends 58, 59 of the ring 55 lies above the complementaryretention structures on the inner member 32. When the ring 55 is in thisposition, there is a reduced contact area between the split ring 55 thecomplementary retention structures thereby reducing the locking strengthbetween the outer sleeve member 53′ and the inner member 32. In theillustrated embodiment, for example, the locking strength may be reducedby about ⅓ when the gap 57 over the complementary retention structuresbetween flat sides 64. As such, it is advantageous to position the gap57 on the flat sides 64 of the inner member 32 that do not includecomplementary retention structures.

To achieve this goal, the illustrated embodiment includes a pair of tabs65, 66 that extend radially inward from the interior of the outer sleevemember 53′. The tabs 65, 66 are configured to limit or preventrotational movement of the ring 55 relative to the housing 62 of theouter sleeve member 53′. In this manner, the gap 57 of the ring 55 maybe positioned over the flattened sides 64 of the inner member 32.

In the illustrated embodiment, the tabs 65, 66 have a generallyrectangular shape and have a generally uniform thickness. However, it iscontemplated that the tabs 65, 66 can be square, curved, or any othersuitable shape for engaging with the ring 55 as described herein.

In the illustrated embodiment, the tabs 65, 66 can be formed by makingan H-shaped cut 67 in the tubular housing 62 and bending the tabs 65, 66inwardly as shown in FIG. 9F. As shown in FIG. 9F, the tabs 65, 66(illustrated in phantom) are interposed between the edges 58, 59 of thering 55. The edges 58, 59 of the ring 55 can contact the tabs to limitthe rotational movement of the ring 55. Those skilled in the art willrecognize that there are many suitable manners for forming the tabs 65,66. In addition, in other embodiments, the tabs 65, 66 may be replacedby a one or more elements or protrusions attached to or formed on theinterior of the outer sleeve member 53′.

Referring again to FIGS. 3-6, the actuator shaft 30 can also comprise atleast one proximal wedge member 68 being disposed at the proximal end 42of the outer sleeve member 34. The proximal wedge member 68 can be sizedand configured to contact the proximal facing surfaces 18, 20 of theupper and lower body portions 14, 16 upon selective relative movement ofthe proximal end 42 of the outer sleeve member 34 toward the distal end36 of the inner member 32. The longitudinal movement of the proximalwedge member 68 against the proximal surfaces 18, 20 can cause theseparation of the upper and lower body portions 14, 16 in order to causethe intervertebral implant 10 to expand from the unexpanded state to theexpanded state, as shown in FIGS. 5 and 6, respectively.

As illustrated in FIGS. 3-6, the proximal wedge member 68 can be formedseparately from the outer sleeve member 34. In such an embodiment,proximal wedge member 68 can be carried on a ring or wedge-typestructure that is fitted around or over the outer sleeve member 34. Inthe illustrated embodiment, the proximal wedge member 68 can taperaxially in the distal direction. For example, as shown in FIGS. 3 and 4,the proximal wedge member 68 can have a triangle-like structure that isdisposed about the actuator shaft 30 and pushed against the proximalsurfaces 18, 20 by the collar 52 of the outer sleeve member 34.

However, in other embodiments, as shown in FIG. 8, the proximal wedgemember 68 can also be integrally formed with and/or permanently coupledto the outer sleeve member 34. Such an embodiment can be advantageous inthat fewer parts are required, which can facilitate manufacturing anduse of the intervertebral implant 10.

Preferably, the proximal surfaces 18, 20 of the upper and lower bodyportions 14, 16 are configured to substantially match the outerconfiguration of the proximal wedge member 68. The proximal surfaces 18,20 can be integrally formed with the upper and lower body portions 14,16 and have a shape that generally tapers toward the proximal ends 22,24. The proximal surfaces 18, 20 can be defined by a smooth and constanttaper, a non-constant curve, or a contact curve, or other geometries asmay be appropriate.

For example, curvature proximal surfaces 18, 20 can be advantageousbecause initial incremental movement of the proximal wedge member 68relative to the distal end 36 of the inner member 32 can result inrelatively larger incremental distances between the upper and lower bodyportions 14, 16 than may subsequent incremental movement of the proximalwedge member 68. Thus, these types of adjustments can allow theclinician to quickly expand the intervertebral implant 10 to an initialexpanded state with few initial incremental movements, but tosubsequently expand the intervertebral implant 10 in smaller and smallerincrements in order to fine tune the placement or expanded state of theintervertebral implant 10. Thus, such embodiments can allow theefficiency of the operation to be improved and allow the clinician tofine tune the expansion of the intervertebral implant 10.

With reference to FIGS. 1 and 5, in the illustrated embodiment, theupper and lower body portions 14, 16 can each have distally facingdistal surfaces 70, 72 disposed at distal ends 74, 76 thereof, assimilarly mentioned above with respect to the proximal surfaces 18, 20.For example, the distal surfaces 70, 72 can be inclined or otherwisecurved with respect to the longitudinal axis of the body portions 14,16. Other features, designs, and configurations of the proximal surfaces18, 20, as disclosed herein, are not repeated with respect to the distalsurfaces 70, 72, but it is understood that such features, designs, andconfigurations can similarly be incorporated into the design of thedistal surfaces 70, 72.

In such an embodiment, the actuator shaft 30 of the intervertebralimplant 10 can further comprise at least one distal wedge member 80 thatcan be disposed at the distal end 36 of the inner member 32. The distalwedge member 80 can be sized and configured to contact the distalsurfaces 70, 72 of the respective ones of the upper and lower bodyportions 14, 16 upon selective relative movement of the distal end 36 ofthe inner member 32 toward the proximal end 42 of the outer sleevemember 34. As similarly described above with respect to the proximalwedge member 68, the longitudinal movement of the distal wedge member 80against the distal surfaces 70, 72 can cause the separation of the upperand lower body portions 14, 16 thereby resulting in expansion of theintervertebral implant 10.

The description of the proximal wedge member 68 and its interaction withthe proximal surfaces 18, 20, as well as the corresponding structuresand embodiments thereof, can likewise be implemented with respect to thedistal wedge member 80 and the distal surfaces 70, 72. Therefore,discussion of alternative embodiments, structures, and functions of thedistal wedge member 80 and the distal surfaces 70, 72 need not berepeated in detail, but can include those mentioned above with respectto the distal wedge member 80 and the distal surfaces 70, 72.

In accordance with yet another embodiment illustrated in FIGS. 10A-11,at least one of the proximal and distal wedge members 68, 80 can beconfigured to include engagement surfaces 90, 92. The engagementsurfaces 90, 92 can include any variety of surface textures, such asridges, protrusions, and the like in order to enhance the engagementbetween the proximal and distal wedge members 68, 80 and the respectiveones of the proximal and distal surfaces 18, 20 and 70, 72. In theembodiment illustrated in FIGS. 10A-11, the engagement surfaces 90, 92can include stepped contours 94, 96, such as comprising a plurality ofridges.

As illustrated in the detail section view of FIG. 10B, the steppedcontours 94, 96 of the engagement surfaces 90, 92 can be preferablyconfigured to be inclined or oriented obliquely with respect to the axisof the actuator shaft 30. The use of the engagement surfaces 90, 92 canpermit one-way, ratchet type longitudinal movement of proximal anddistal wedge members 68, 80 relative to the proximal and distal surfaces18, 20 and 70, 72 in order to maintain the upper and lower body portions14, 16 at a given separation distance.

Additionally, at least one of the proximal and distal surfaces 18, 20and 70, 72 of the upper and lower body portions 14, 16 can includecomplimentary engagement surfaces 100, 102, 104, 106. The complimentaryengagement surfaces 100, 102, 104, 106 can similarly include any varietyof surface textures, such as ridges, protrusions, and the like in orderto enhance the engagement between the respective ones of the distal andproximal protrusions 68, 80.

In accordance with the embodiment shown in FIGS. 10A-11, thecomplimentary engagement surfaces 100, 102, 104, 106 can be configuredas stepped contours 108, 110 and 112, 114, such as including a pluralityof ridges. As shown best in the detail section view of FIG. 10, thestepped contours 108, 110, 112, 114 can also be configured to beinclined or oriented obliquely with respect to the axis of the actuatorshaft 30. However, the stepped contours 108, 110, 112, 114 arepreferably inclined in a direction opposite to the stepped contours 94,96 of the proximal and distal wedge members 68, 80.

In such an embodiment, the stepped contours 108, 110, 112, 114 canengage the stepped contours 94, 96 of the wedge members 68, 80 to permitone-way ratcheting of the proximal and distal wedge members 68, 80 alongthe proximal and distal surfaces 18, 20, 70, 72. This advantageousfeature can be incorporated into various embodiments disclosed herein inorder to, inter alia, further improve the deployment and stabilizationof the intervertebral implant 10.

As shown in FIGS. 10A, in this embodiment, the inner member 32 and theouter sleeve member 34 do not include complementary retention structuresas described above with reference to FIGS. 3 and 4. Thus, in thisembodiment the inner members 32 can be moved with respect to the outersleeve member 34, and the above-described engagement between theproximal and distal wedge members 68, 80 and the respective ones of thedistal and proximal surfaces 18, 20 and 70, 72 can provide ratchet-typemovement and maintain expansion of the implant 10. However, in modifiedembodiments, the retention structures 40, 44 of the actuator shaft 30can also be provided in addition to the engagement of the proximal anddistal wedge members 68, 80 and the respective ones of the distal andproximal surfaces 18, 20 and 70, 72.

Referring again to FIGS. 3 and 4, according to the illustratedembodiment , the intervertebral implant 10 can further comprise at leastone alignment guide 120. The alignment guide 120 can be connected to theupper and lower body portions 14, 16 and be operative to facilitateseparation of the first and second body portions 14, 16. As shown inFIGS. 3 and 4, the alignment guide 120 can comprise a plurality of guiderods 122 that are disposed through corresponding bores in the upper andlower body portions 14, 16. The rods 122 can be configured to orient theupper body portion 14 substantially orthogonally with respect to an axisof the actuator shaft 30 and with respect to the lower body portion 16.In such an embodiment, the rods 122 can each include a telescopingmechanism to enable and stabilize expansion of the intervertebralimplant 30. Preferably, the alignment guide 120 also facilitatesexpansion or separation of the upper and lower body portions 14, 16 in adirection substantially orthogonal to an axis of the actuator shaft 30,such as in the axial direction of the rods 122.

In accordance with another embodiment illustrated in FIGS. 12 and 13,the alignment guide 120 can also be configured to include a first pairof side rails 130 extending from the upper body portion 14 toward thelower body portion 16 for aligning the upper body portion 14 with thelower body portion 16 to facilitate separation of the upper and lowerbody portions 14, 16 in a direction substantially orthogonal to an axisof the actuator shaft 30. Further, the alignment guide 120 can alsoinclude a second pair of side rails 132 extending from the lower bodyportion 16 toward the upper body portion 14 for cooperating with thefirst pair of side rails 130 in aligning the upper body portion 14 withthe lower body portion 16 to facilitate separation of the upper andlower body portions 14, 16 in a direction substantially orthogonal tothe axis of the actuator shaft 30.

As shown, the first and second pairs of side rails 130, 132 can beconfigured to extend substantially orthogonally from the respective onesof the upper and lower body portions 14, 16. In this regard, althoughthe upper and lower body portions 14, 16 are illustrated as beingconfigured substantially as parallel plates, any variety ofconfigurations can be provided, such as generally ovular, wedge-shaped,and others, as mentioned above. Thus, the first and second pairs of siderails 130, 132 can be configured accordingly depending upon theconfiguration and design of the upper and lower body portions 14, 16.

For example, it is contemplated that the first and second pairs of siderails 130, 132 can be configured to ensure that the spacing between theproximal ends 22, 24 of the respective ones of the upper and lower bodyportions 14, 16 is equal to the spacing between the distal ends 74, 76thereof. However, the first and second pairs of side rails 130, 132 canalso be configured to orient exterior surfaces of the upper and lowerbody portions 14, 16 at an oblique angle relative to each other. Thus,the spacing between the proximal ends 22, 24 of the respective ones ofthe upper and lower body portions 14, 16 can be different from thespacing between the distal ends 74, 76 thereof. Thus, in one embodiment,such orientation can be created depending upon the desired configurationof the first and second pairs of side rails 130, 132.

Further, it is contemplated that the first and second pairs of siderails 130, 132 can be linear or planar in shape, as well as to generallyconform to the shape of a curve in the longitudinal direction.Furthermore, the first and second pairs of side rails 130, 132 can alsobe configured to include mating surfaces to facilitate expansion andalignment of the intervertebral implant 10. Finally, the first andsecond pairs of side rails 130, 132, although illustrated as solid, caninclude perforations or other apertures to provide circulation throughthe intervertebral space.

In accordance with yet another embodiment, a method of implanting orinstalling the spinal fusion implant 10 is also provided. The method cancomprise the steps of positioning the intervertebral implant 10 betweentwo vertebral bodies and moving the inner member 32 of the actuatorshaft 30 in an proximal direction relative to the outer sleeve member 34to force the proximal wedge member 68 and distal wedge member 80 againstthe proximal and distal surfaces 18, 20, 70, 72 of upper and lower bodyportions 14, 16 of the intervertebral implant 10 to separate the upperand lower body portions 14, 16 to cause the intervertebral implant 10 toexpand intermediate the vertebral bodies. The method can be accomplishedutilizing the various embodiments as described herein.

For any of the embodiments disclosed above, installation can besimplified through the use of the installation equipment. Theinstallation equipment can comprise a pistol grip or plier-type grip sothat the clinician can, for example, position the equipment at theproximal extension of actuator shaft 30, against the proximal end 42 ofthe outer sleeve member 34, and through one or more contractions withthe hand, the proximal end 42 of the outer sleeve member 34 and thedistal end 36 of the inner member 32 can be drawn together toappropriately tension.

In particular, while proximal traction is applied to the proximal end 38of the inner member 32, appropriate tensioning of the actuator shaft 30is accomplished by tactile feedback or through the use of a calibrationdevice for applying a predetermined load on the actuator shaft 30.Following appropriate tensioning of the actuator shaft 30, the proximalextension of the actuator shaft 30 (or the tool 50) is preferablyremoved, such as by being unscrewed, cut off or snapped off. Such a cutcan be made using conventional saws, cutters or bone forceps which areroutinely available in the clinical setting.

In certain embodiments, the proximal extension of the actuator shaft 30may be removed by cauterizing. Cauterizing the proximal extension mayadvantageously fuse the proximal end 38 of the inner member 32 to thedistal end 42 of the outer sleeve member 34, thereby adding to theretention force between the outer sleeve member 34 and the inner member30 and between the proximal and distal protrusions 68, 80 and therespective ones of the distal and proximal surfaces 18, 20 and 70, 72,if applicable. Such fusion between the proximal end 38 of the innermember 32 to the distal end 42 of the outer sleeve member 34 may beparticularly advantageous if the intervertebral implant 10 is made froma bioabsorbable and/or biodegradable material. In this manner, as thematerial of the proximal anchor and/or the actuator shaft is absorbed ordegrades, the fusion caused by the cauterizing continues to provideretention force between the proximal anchor and the pin.

Following trimming the proximal end of actuator shaft 30, the accesssite may be closed and dressed in accordance with conventional woundclosure techniques.

Preferably, the clinician will have access to an array of intervertebralimplants 10, having different widths and axial lengths. These may bepackaged one or more per package in sterile envelopes or peelablepouches. Upon encountering an intervertebral space for which the use ofa intervertebral implant 10 is deemed appropriate, the clinician willassess the dimensions and load requirements of the spine 12, and selectan intervertebral implant 10 from the array which meets the desiredspecifications.

The embodiments described above may be used in other anatomical settingsbeside the spine. As mentioned above, the embodiments described hereinmay be used for spinal fixation. In embodiments optimized for spinalfixation in an adult human population, the upper and lower portions 14,15 will generally be within the range of from about 10-60 mm in lengthand within the range of from about 5-30 mm in maximum width and thedevice can expand from a height of about 5 mm to about 30 mm.

For the embodiments discussed herein, the intervertebral implantcomponents can be manufactured in accordance with any of a variety oftechniques which are well known in the art, using any of a variety ofmedical-grade construction materials. For example, the upper and lowerbody portions 14, 16, the actuator shaft 30, and other components can beinjection-molded from a variety of medical-grade polymers including highor other density polyethylene, PEEK™ polymers, nylon and polypropylene.Retention structures 40, 44 can also be integrally molded with theactuator shaft 30. Alternatively, retention structures 40, 44 can bemachined or pressed into the actuator shaft 30 in a post-moldingoperation, or secured using other techniques depending upon theparticular design. The retention structures 40, 44 can also be made of adifferent material.

The intervertebral implant 10 components can be molded, formed ormachined from biocompatible metals such as Nitinol, stainless steel,titanium, and others known in the art. Non-metal materials such asplastics, PEEK™ polymers, and rubbers can also be used. Further, theimplant components can be made of combinations of PEEK™ polymers andmetals. In one embodiment, the intervertebral implant components can beinjection-molded from a bioabsorbable material, to eliminate the needfor a post-healing removal step.

The intervertebral implant components may contain one or more bioactivesubstances, such as antibiotics, chemotherapeutic substances, angiogenicgrowth factors, substances for accelerating the healing of the wound,growth hormones, antithrombogenic agents, bone growth accelerators oragents, and the like. Such bioactive implants may be desirable becausethey contribute to the healing of the injury in addition to providingmechanical support.

In addition, the intervertebral implant components may be provided withany of a variety of structural modifications to accomplish variousobjectives, such as osteoincorporation, or more rapid or uniformabsorption into the body. For example, osteoincorporation may beenhanced by providing a micropitted or otherwise textured surface on theintervertebral implant components. Alternatively, capillary pathways maybe provided throughout the intervertebral implant, such as bymanufacturing the intervertebral implant components from an open cellfoam material, which produces tortuous pathways through the device. Thisconstruction increases the surface area of the device which is exposedto body fluids, thereby generally increasing the absorption rate.Capillary pathways may alternatively be provided by laser drilling orother technique, which will be understood by those of skill in the artin view of the disclosure herein. Additionally, apertures can beprovided in the implant to facilitate packing of biologics into theimplant, backfilling, and/or osseointegration of the implant. Ingeneral, the extent to which the intervertebral implant can be permeatedby capillary pathways or open cell foam passageways may be determined bybalancing the desired structural integrity of the device with thedesired reabsorption time, taking into account the particular strengthand absorption characteristics of the desired polymer.

The intervertebral implant may be sterilized by any of the well knownsterilization techniques, depending on the type of material. Suitablesterilization techniques include heat sterilization, radiationsterilization, such as cobalt irradiation or electron beams, ethyleneoxide sterilization, and the like.

Referring now to FIGS. 14A-14D, various modified configurations andapplications of the implant are illustrated. As mentioned above, theembodiments, applications, and arrangements disclosed herein can bereadily modified by one of skill in order to suit the requirements ofthe clinician. It will therefore be appreciated that embodimentsdisclosed herein are not limited to those illustrated, but can becombined and/or modified.

FIG. 14A is a side view of another embodiment of an intervertebralimplant 10 wherein the upper and lower body portions 14, 16 havegenerally slanted configurations. As illustrated, the upper and lowerbody portions 14, 16 can define generally convex upper and lowersurfaces 140, 142, respectively. Such an embodiment can be beneficialespecially in applications where the implant 10 must complement thenatural curvature of the spine. The upper and lower surfaces 140, 142can generally match the concavity of adjacent upper and lower vertebralbodies. It will be appreciated that the slanted configuration can bemodified and a range of curvatures can be accommodated as required.Furthermore, the upper and lower surfaces 140, 142 can be generallyplanar and oriented at an angle relative to each other. In someembodiments, the upper and lower surfaces 140, 142 of the implant 10 canbe formed such that the implant defines a generally wedge-shaped design.The dimensions of the implant 10 can be varied as desired.

As illustrated in FIG. 14A, the upper and lower body portions 14, 16 canbe configured such that exterior surfaces thereof are oriented obliquelywith respect to interior surfaces thereof. For example, in someembodiments, the upper and lower body portions 14, 16 can be configuredgenerally as wedges. However, as also mentioned with regard to FIGS. 12and 13, it is also contemplated that the actuation mechanism of theimplant can allow the spacing between the proximal ends of therespective ones of the upper and lower body portions to be differentfrom of the spacing between the distal ends thereof due to the overallconfiguration of the implant.

In this regard, the angular relationship between the upper and lowerbody portions 14, 16 can be varied as desired. For example, the spacingof the distal ends of the upper and lower body portions 14, 16 canincrease at a greater rate as the implant is expanded that the spacingbetween the proximal ends of the upper and lower body portions 14, 16,or vice versa. This feature can result from the interaction of theactuator shaft with the implant, the wedges with the upper and lowerbody portions 14, 16, or the actuator shaft with the wedges. It iscontemplated, for example, that the distal and proximal wedges can havedifferent configurations with different angular relationships betweentheir contact surfaces. Further, the actuator shaft can have differentthread configurations such that one wedge advances faster than the otherwedge upon rotation of the pin. Alternative embodiments can also bedeveloped based on the present disclosure.

Referring now to FIG. 14B, a top view of another embodiment of anintervertebral implant 10 is provided wherein the implant 10 has agenerally clamshell configuration. Such an embodiment can be beneficialin applications where the clinician desires to support the vertebraeprincipally about their peripheral aspects.

For example, at least one of the upper and lower body portions 14, 16can be configured to have a semicircular face. When such an embodimentis implanted and deployed in a patient, the outwardly bowed portions ofthe upper and lower body portions 14, 16 provide a footprint that allowsthe implant 10 to contact the vertebrae about their periphery, asopposed to merely supporting the vertebrae in a substantially central oraxial location. In such embodiments, the upper and lower body portions14, 16 can thus be banana or crescent shaped to facilitate contact withcortical bone. Thus, such embodiments can employ the more durable,harder structure of the periphery of the vertebrae to support the spine.

In an additional embodiment, FIG. 14C shows a top view of anintervertebral implant 10 illustrating that the implant 10 can have agenerally square configuration and footprint when implanted into theintervertebral space of the spine 12. Such a configuration would likelybe utilized in a more invasive procedure, rather than in percutaneousapplications. As mentioned above with respect to FIG. 14B, the footprintof such an embodiment can allow the implant 10 to more fully contact themore durable, harder portions of the vertebrae to facilitate support andhealing of the spine. Alternative embodiments can be created thatprovide ovular, circular, hexagonal, rectangular, and any other shapedfootprint.

Furthermore, FIG. 14D is a top view of the spine 12 illustrating anexemplary application of the intervertebral implant. In this example, aplurality of intervertebral implants 10′ and 10″ (shown in hidden lines)can be disposed in an intervertebral space of the spine 12 to supportadjacent vertebrae. As mentioned above, one of the beneficial aspects ofembodiments of the implant provides that the implant can be used inpercutaneous applications.

In FIG. 14D, it is illustrated that one or more implants 10′ can beimplanted and oriented substantially parallel with respect to each otherin order to support the adjacent vertebrae. Also shown, at least twoimplants 10″ can be implanted and oriented transversely with respect toeach other in order to support the adjacent vertebrae. In addition, itis contemplated that a cross-midline approach can be used wherein asingle implant is placed into the intervertebral space in an orientationas depicted for one of the implants 10′, although more centrally. Thus,the angular orientation of the implant(s) can be varied. Further, thenumber of implants used in the spinal fusion procedure can also bevaried to include one or more. Other such configurations, orientations,and operational parameters are contemplated in order to aid theclinician in ensuring that the adjacent vertebrae are properlysupported, and that such procedure is performed in a minimally invasivemanner.

Referring now to FIG. 15, yet another embodiment is provided. FIG. 15 isa side view of an intervertebral implant 10 in an unexpanded state inwhich a screw mechanism 150 can be utilized to draw the proximal anddistal wedged members 68, 80 together to cause the implant to move to anexpanded state. Thus, a rotational motion, instead of a translationalmotion (as discussed above in reference to other embodiments) can beutilized to cause the implant 10 to move to its expanded state.

In some embodiments, the screw mechanism 150 can comprise an Archimedesscrew, a jack bolt, or other fastener that can cause the convergence oftwo elements that are axially coupled to the fastener. The screwmechanism 150 can have at least one thread disposed along at least aportion thereof, if not along the entire length thereof

Further, the screw mechanism can be threadably attached to one or bothof the proximal and distal wedge members 68, 80. As illustrated in FIG.15, the distal wedge member 80 can also be freely rotatably attached tothe screw mechanism 150 while the proximal wedge member 68 is threadablyattached thereto. Further, as disclosed above with respect to the pin,the screw mechanism 150 can also be configured such that a proximalportion of the screw mechanism 150 can be removed after the implant 10has been expanded in order to eliminate any proximal protrusion of thescrew mechanism 150.

Therefore, in the illustrated embodiment, it is contemplated that uponrotation of the screw mechanism 150, the proximal and distal wedgedmembers 68, 80 can be axially drawn closer together. As a result of thisaxial translation, the proximal and distal wedged members 68, 80 cancontact the respective ones of the proximal and distal surfaces 18, 20and 70, 72 in order to facilitate separation of the upper and lower bodyportions 14, 16, as similarly disclosed above.

The screw mechanism 150 can be utilized to provide a stabilizing axialforce to the proximal and distal wedge members 68, 80 in order tomaintain the expansion of the implant 10. However, it is alsocontemplated that other features can be incorporated into such anembodiment to facilitate the maintenance of the expansion. In thisregard, although the axial force provided by the screw mechanism 150 cantend to maintain the position and stability of the proximal and distalwedge members 68, 80, additional features can be employed to ensure thestrength and stability of the implant 10 when in its expanded state.

For example, as discussed above with respect to FIGS. 10A-10B, theproximal and distal wedge members 68, 80 can include engagement surfaces90, 92, such as stepped contours 94, 96. As discussed above, the use ofthe engagement surfaces 90, 92 can permit one-way, ratchet typelongitudinal movement of proximal and distal wedge members 68, 80relative to the proximal and distal surfaces 18, 20 and 70, 72 in orderto maintain the upper and lower body portions 14, 16 at a givenseparation distance.

Furthermore, as also disclosed above, at least one of the proximal anddistal surfaces 18, 20 and 70, 72 of the upper and lower body portions14, 16 can include complimentary engagement surfaces 100, 102, 104, 106to enhance the engagement between the respective ones of the distal andproximal protrusions 68, 80. In an embodiment, the complimentaryengagement surfaces 100, 102, 104, 106 can be configured as steppedcontours 108, 110 and 112, 114. Thus, the stepped contours 108, 110,112, 114 can engage the stepped contours 94, 96 of the wedge members 68,80 to permit one-way ratcheting of the proximal and distal wedge members68, 80 along the proximal and distal surfaces 18, 20, 70, 72.

Therefore, some embodiments can be configured such that a rotationalmotion can be exerted on the actuator shaft or screw mechanism, insteadof a pulling or translational motion, in order to expand an embodimentof the implant from an unexpanded state (such as that illustrated inFIG. 12) to an expanded state (such as that illustrated in FIG. 13).Such embodiments can be advantageous in certain clinical conditions andcan provide the clinician with a variety of options for the benefit ofthe patient. Further, the various advantageous features discussed hereinwith respect to other embodiments can also be incorporated into suchembodiments.

Referring now to FIG. 16A-19, another embodiment of the implant isillustrated. FIG. 16A is a perspective view of an intervertebral implant200 in an unexpanded state. The implant 200 can comprise upper and lowerbody portions 202, 204, proximal and distal wedge members 206, 208, andan actuator shaft 210. In the unexpanded state, the upper and lower bodyportions 202, 204 can be generally abutting with a height of the implant200 being minimized. However, the implant 200 can be expanded, as shownin FIG. 16B to increase the height of the implant 200 when implantedinto the intervertebral space of the spine.

In some embodiments, the height of the implant 200 can be betweenapproximately 7-15 mm, and more preferably, between approximately 8-13mm. The width of the implant can be between approximately 7-11 mm, andpreferably approximately 9 mm. The length of the implant 200 can bebetween approximately 18-30 mm, and preferably approximately 22 mm.Thus, the implant 200 can have a preferred aspect ratio of betweenapproximately 7:11 and 15:7, and preferably approximately between 8:9and 13:9. It is contemplated that various modifications to the dimensiondisclosed herein can be made by one of skill and the mentioneddimensions shall not be construed as limiting.

Additionally, as noted above, the implant 200 can also be made usingnon-metal materials such as plastics, PEEK™ polymers, and rubbers.Further, the implant components can be made of combinations of PEEK™polymers and metals. Accordingly, the implant 200 can be at leastpartially radiolucent, which radiolucency can allow a doctor to perceivethe degree of bone growth around and through the implant. The individualcomponents of the implant 200 can be fabricated of such materials basedon needed structural, biological and optical properties.

As discussed generally above with respect to FIG. 15, it is contemplatedthat the actuator shaft 210 can be rotated to cause the proximal anddistal wedge members to move toward each other, thus causing the upperand lower body portions 202, 204 to be separated. Although, the presentembodiment is illustrated using this mode of expansion, it iscontemplated that other modes of expansion described above (e.g., oneway-ratchet type mechanism) can be combined with or interchangedherewith.

In some embodiments, the implant 200 can be configured such that theproximal and distal wedge members 206, 208 are interlinked with theupper and lower body portions 202, 204 to improve the stability andalignment of the implant 200. For example, the upper and lower bodyportions 202, 204 can be configured to include slots (slot 220 is shownin FIG. 16A, and slots 220, 222 are shown in FIG. 16B; the configurationof such an embodiment of the upper and lower body portions 202, 204 isalso shown in FIGS. 20A-21B, discussed below). In such an embodiment,the proximal and distal wedge members 206, 208 can be configured toinclude at least one guide member (an upper guide member 230 of theproximal wedge member 206 is shown in FIG. 16A and an upper guide member232 of the distal wedge member 208 is shown in FIG. 18) that at leastpartially extends into a respective slot of the upper and lower bodyportions. The arrangement of the slots and the guide members can enhancethe structural stability and alignment of the implant 200.

In addition, it is contemplated that some embodiments of the implant 200can be configured such that the upper and lower body portions 202, 204each include side portions (shown as upper side portion 240 of the upperbody portion 202 and lower side portion 242 of the lower body portion204) that project therefrom and facilitate the alignment,interconnection, and stability of the components of the implant 200.FIG. 16B is a perspective view of the implant 200 wherein the implant200 is in the expanded state. The upper and lower side portions 240, 242can be configured to have complementary structures that enable the upperand lower body portions 202, 204 to move in a vertical direction.Further, the complementary structures can ensure that the proximal endsof the upper and lower body portions 202, 204 generally maintain spacingequal to that of the distal ends of the upper and lower body portions202, 204. The complementary structures are discussed further below withregard to FIGS. 17-21B.

Furthermore, as described further below, the complementary structurescan also include motion limiting portions that prevent expansion of theimplant beyond a certain height. This feature can also tend to ensurethat the implant is stable and does not disassemble during use.

In some embodiments, the actuator shaft 210 can facilitate expansion ofthe implant 200 through rotation, longitudinal contract of the pin, orother mechanisms. The actuator shaft 210 can include threads thatthreadably engage at least one of the proximal and distal wedge members206, 208. The actuator shaft 210 can also facilitate expansion throughlongitudinal contraction of the actuator shaft as proximal and distalcollars disposed on inner and outer sleeves move closer to each other toin turn move the proximal and distal wedge members closer together, asdescribed above with respect to actuator shaft 30 shown in FIGS. 5-6. Itis contemplated that in other embodiments, at least a portion of theactuator shaft can be axially fixed relative to one of the proximal anddistal wedge members 206, 208 with the actuator shaft being operative tomove the other one of the proximal and distal wedge members 206, 208 viarotational movement or longitudinal contraction of the pin.

Further, in embodiments wherein the actuator shaft 210 is threaded, itis contemplated that the actuator shaft 210 can be configured to bringthe proximal and distal wedge members closer together at differentrates. In such embodiments, the implant 200 could be expanded to aV-configuration or wedged shape. For example, the actuator shaft 210 cancomprise a variable pitch thread that causes longitudinal advancement ofthe distal and proximal wedge members at different rates. Theadvancement of one of the wedge members at a faster rate than the othercould cause one end of the implant to expand more rapidly and thereforehave a different height that the other end. Such a configuration can beadvantageous depending on the intervertebral geometry and circumstantialneeds.

In other embodiments, the implant 200 can be configured to includeanti-torque structures 250. The anti-torque structures 250 can interactwith at least a portion of a deployment tool during deployment of theimplant to ensure that the implant maintains its desired orientation(see FIGS. 25-26 and related discussion). For example, when the implant200 is being deployed and a rotational force is exerted on the actuatorshaft 210, the anti-torque structures 250 can be engaged by anon-rotating structure of the deployment tool to maintain the rotationalorientation of the implant 200 while the actuator shaft 210 is rotated.The anti-torque structures 250 can comprise one or more inwardlyextending holes or indentations on the proximal wedge member 206, whichare shown as a pair of holes in FIGS. 16A-B. However, the anti-torquestructures 250 can also comprise one or more outwardly extendingstructures.

According to yet other embodiments, the implant 200 can be configured toinclude one or more apertures 252 to facilitate osseointegration of theimplant 200 within the intervertebral space. As mentioned above, theimplant 200 may contain one or more bioactive substances, such asantibiotics, chemotherapeutic substances, angiogenic growth factors,substances for accelerating the healing of the wound, growth hormones,antithrombogenic agents, bone growth accelerators or agents, and thelike. Indeed, various biologics can be used with the implant 200 and canbe inserted into the disc space or inserted along with the implant 200.The apertures 252 can facilitate circulation and bone growth throughoutthe intervertebral space and through the implant 200. In suchimplementations, the apertures 252 can thereby allow bone growth throughthe implant 200 and integration of the implant 200 with the surroundingmaterials.

FIG. 17 is a bottom view of the implant 200 shown in FIG. 16A. As showntherein, the implant 200 can comprise one or more protrusions 260 on abottom surface 262 of the lower body portion 204. Although not shown inthis FIG., the upper body portion 204 can also define a top surfacehaving one or more protrusions thereon. The protrusions 260 can allowthe implant 200 to engage the adjacent vertebrae when the implant 200 isexpanded to ensure that the implant 200 maintains a desired position inthe intervertebral space.

The protrusions 260 can be configured in various patterns. As shown, theprotrusions 260 can be formed from grooves extending widthwise along thebottom surface 262 of the implant 200 (also shown extending from a topsurface 264 of the upper body portion 202 of the implant 200). Theprotrusions 260 can become increasingly narrow and pointed toward theirapex. However, it is contemplated that the protrusions 260 can be one ormore raised points, cross-wise ridges, or the like.

FIG. 17 also illustrates a bottom view of the profile of an embodimentof the upper side portion 240 and the profile of the lower side portion242. As mentioned above, the upper and lower side portions 240, 242 caneach include complementary structures to facilitate the alignment,interconnection, and stability of the components of the implant 200.FIG. 17 also shows that in some embodiments, having a pair of each ofupper and lower side portions 240, 242 can ensure that the upper andlower body portions 202, 204 do not translate relative to each other,thus further ensuring the stability of the implant 200.

As illustrated in FIG. 17, the upper side portion 240 can comprise agroove 266 and the lower side portion can comprise a rib 268 configuredto generally mate with the groove 266. The groove 266 and rib 268 canensure that the axial position of the upper body portion 202 ismaintained generally constant relative to the lower body portion 204.Further, in this embodiment, the grooves 266 and rib 268 can also ensurethat the proximal ends of the upper and lower body portions 202, 204generally maintain spacing equal to that of the distal ends of the upperand lower body portions 202, 204. This configuration is alsoillustratively shown in FIG. 18.

Referring again to FIG. 17, the implant 200 is illustrated in theunexpanded state with each of the respective slots 222 of the lower bodyportion 204 and lower guide members 270, 272 of the respective ones ofthe proximal and distal wedge members 206, 208. In some embodiments, asshown in FIGS. 16A-17 and 19-21B, the slots and guide members can beconfigured to incorporate a generally dovetail shape. Thus, once a givenguide member is slid into engagement with a slot, the guide member canonly slide longitudinally within the slot and not vertically from theslot. This arrangement can ensure that the proximal and distal wedgemembers 206, 208 are securely engaged with the upper and lower bodyportions 202, 204.

Furthermore, in FIG. 18, a side view of the embodiment of the implant200 in the expanded state illustrates the angular relationship of theproximal and distal wedge members 206, 208 and the upper and lower bodyportions 202, 204. As mentioned above, the dovetail shape of the slotsand guide members ensures that for each given slot and guide member, agiven wedge member is generally interlocked with the give slot to onlyprovide one degree of freedom of movement of the guide member, and thusthe wedge member, in the longitudinal direction of the given slot.

Accordingly, in such an embodiment, the wedge members 206, 208 may notbe separable from the implant when the implant 200 is in the unexpandedstate (as shown in FIG. 16A) due to the geometric constraints of theangular orientation of the slots and guide members with the actuatorshaft inhibiting longitudinal relative movement of the wedge members206, 208 relative to the upper and lower body portions 202, 204. Such aconfiguration ensures that the implant 200 is stable and structurallysound when in the unexpanded state or during expansion thereof, thusfacilitating insertion and deployment of the implant 200.

Such an embodiment of the implant 200 can therefore be assembled byplacing or engaging the wedge members 206, 208 with the actuator shaft210, moving the wedge members 206, 208 axially together, and insertingthe upper guide members 230, 232 into the slots 220 of the upper bodyportion 202 and the lower guide members 270, 272 into the slots 222 ofthe lower body portion 204. The wedge members 206, 208 can then be movedapart, which movement can cause the guide members and slots to engageand bring the upper and lower body portions toward each other. Theimplant 200 can then be prepared for insertion and deployment byreducing the implant 200 to the unexpanded state.

During assembly of the implant 200, the upper and lower body portions202, 204 can be configured to snap together to limit expansion of theimplant 200. For example, the upper and lower side portions 240, 242 cancomprise upper and lower motion-limiting structures 280, 282, as shownin the cross-sectional view of FIG. 19. After the wedge members 206, 208are engaged with the upper and lower body portions 202, 204 and axiallyseparated to bring the upper and lower body portions 202, 204 together,the upper motion-limiting structure 280 can engage the lowermotion-limiting structure 282. This engagement can occur due todeflection of at least one of the upper and lower side portions 240,242. However, the motion-limiting structures 280, 282 preferablycomprise interlocking lips or shoulders to engage one another when theimplant 200 has reached maximum expansion. Accordingly, after the wedgemembers 206, 208 are assembled with the upper and lower body portions202, 204, these components can be securely interconnected to therebyform a stable implant 200.

Referring again to FIG. 18, the implant 200 can define generally convextop and bottom surfaces 264, 262. This shape, as discussed above withrespect to FIG. 14A, can be configured to generally match the concavityof adjacent vertebral bodies.

FIGS. 20A-B illustrate perspective views of the lower body portion 204of the implant 200, according to an embodiment. These FIGS. provideadditional clarity as to the configuration of the slots 222, the lowerside portions 242, and the lower motion-limiting members 282 of thelower body portion 204. Similarly, FIGS. 21A-B illustrate perspectiveviews of the upper body portion 202 of the implant 200, according to anembodiment. These FIGS. provide additional clarity as to theconfiguration of the slots 220, the upper side portions 240, and theupper motion-limiting members 280 of the upper body portion 202.Additionally, the upper and lower body portions 202, 204 can also definea central receptacle 290 wherein the actuator shaft can be received.Further, as mentioned above, the upper and lower body portions 202, 204can define one or more apertures 252 to facilitate osseointegration.

FIG. 22 is a perspective view of an actuator shaft 210 of the implant200 shown in FIG. 16A. In this embodiment, the actuator shaft 210 can bea single, continuous component having threads 294 disposed thereon forengaging the proximal and distal wedge members 206, 208. The threads canbe configured to be left hand threads at a distal end of the actuatorshaft 210 and right hand threads at a proximal other end of the actuatorshaft for engaging the respective ones of the distal and proximal wedgemembers 208, 206. Accordingly, upon rotation of the actuator shaft 210,the wedge members 206, 208 can be caused to move toward or away fromeach other to facilitate expansion or contraction of the implant 200.Further, as noted above, although this embodiment is described andillustrated as having the actuator shaft 210 with threads 294, it isalso contemplated that relative movement of the wedge members can beachieved through the use of the actuator shaft 30 described in referenceto FIGS. 5-6, and that such an actuator shaft could likewise be usedwith the embodiment shown in FIGS. 16A-19.

In accordance with an embodiment, the actuator shaft 210 can alsocomprise a tool engagement section 296 and a proximal engagement section298. The tool engagement section 296 can be configured as a to beengaged by a tool, as described further below. The tool engagementsection 296 can be shaped as a polygon, such as a hex shape. As shown,the tool engagement section 296 is star shaped and includes six points,which configuration tends to facilitate the transfer of torque to theactuator shaft 210 from the tool. Other shapes and configurations canalso be used.

Furthermore, the proximal engagement section 298 of the actuator shaft210 can comprise a threaded aperture. The threaded aperture can be usedto engage a portion of the tool for temporarily connecting the tool tothe implant 200. It is also contemplated that the proximal engagementsection 298 can also engage with the tool via a snap or press fit.

FIG. 23A-B illustrate perspective views of the proximal wedge member 206of the implant 200. As described above, the proximal wedge member caninclude one or more anti-torque structures 250. Further, the guidemembers 230, 270 are also illustrated. The proximal wedge member 206 cancomprise a central aperture 274 wherethrough an actuator shaft can bereceived. When actuator shaft 210 is used in an embodiment, the centralaperture 274 can be threaded to correspond to the threads 294 of theactuator shaft 210. In other embodiments, the actuator shaft can engageother portions of the wedge member 206 for causing expansion orcontraction thereof

FIG. 24A-B illustrate perspective views of the distal wedge member 208of the implant 200. As similarly discussed above with respect to theproximal wedge member 206, the guide members 232, 272 and a centralaperture 276 of the proximal wedge member 206 are illustrated. Thecentral aperture 276 can be configured to receive an actuator shafttherethrough. When actuator shaft 210 is used in an embodiment, thecentral aperture 276 can be threaded to correspond to the threads 294 ofthe actuator shaft 210. In other embodiments, the actuator shaft canengage other portions of the wedge member 208 for causing expansion orcontraction thereof

Referring now to FIG. 25, there is illustrated a perspective view of adeployment tool 400 according to another embodiment. The tool 400 cancomprise a handle section 402 and a distal engagement section 404. Thehandle portion 402 can be configured to be held by a user and cancomprise various features to facilitate implantation and deployment ofthe implant.

According to an embodiment, the handle section 402 can comprise a fixedportion 410, and one or more rotatable portions, such as the rotatabledeployment portion 412 and the rotatable teathering portion 414. In suchan embodiment, the teathering portion 414 can be used to attach theimplant to the tool 400 prior to insertion and deployment. Thedeployment portion 412 can be used to actuate the implant and rotate theactuator shaft thereof for expanding the implant. Then, after theimplant is expanded and properly placed, the teathering portion 414 canagain be used to unteather or decouple the implant from the tool 400.

Further, the distal engagement section 404 can comprise a fixed portion420, an anti-torque component 422, a teathering rod (element 424 shownin FIG. 26), and a shaft actuator rod (element 426 shown in FIG. 26) tofacilitate engagement with and actuation of the implant 200. Theanti-torque component 422 can be coupled to the fixed portion 420. Asdescribed above with reference to FIGS. 16A-B, in an embodiment, theimplant 200 can comprise one or more anti-torque structures 250. Theanti-torque component 422 can comprise one or more protrusions thatengage the anti-torque structures 250 to prevent movement of the implant200 when a rotational force is applied to the actuator shaft 210 via thetool 400. As illustrated, the anti-torque component 422 can comprise apair of pins that extend from a distal end of the tool 400. However, itis contemplated that the implant 200 and tool 400 can be variouslyconfigured such that the anti-torque structures 250 and the anti-torquecomponent 422 interconnect to prevent a torque being transferred to theimplant 200. The generation of the rotational force will be explained ingreater detail below with reference to FIG. 26, which is a side-crosssectional view of the tool 400 illustrating the interrelationship of thecomponents of the handle section 402 and the distal engagement section404.

For example, as illustrated in FIG. 26, the fixed portion 410 of thehandle section 402 can be interconnected with the fixed portion 420 ofthe distal engagement section 404. The distal engagement section 404 canbe configured with the deployment portion 412 being coupled with theshaft actuator rod 426 and the teathering portion 414 being coupled withthe teathering rod 424. Although these portions can be coupled to eachother respectively, they can move independently of each other andindependently of the fixed portions. Thus, while holding the fixedportion 410 of the handle section 402, the deployment portion 412 andthe teathering portion 414 can be moved to selectively expand orcontract the implant or to attach the implant to the tool, respectively.In the illustrated embodiment, these portions 412, 414 can be rotated tocause rotation of an actuator shaft 210 of an implant 200 engaged withthe tool 400.

As shown in FIG. 26, the teather rod 424 can comprise a distalengagement member 430 being configured to engage a proximal end of theactuator shaft 210 of the implant 200 for rotating the actuator shaft210 to thereby expand the implant from an unexpanded state to andexpanded state. The teather rod 424 can be configured with the distalengagement member 430 being a threaded distal section of the rod 424that can be threadably coupled to an interior threaded portion of theactuator shaft 210. As mentioned above, the anti-torque component 422 ofthe

In some embodiments, the tool 400 can be prepared for a single-use andcan be packaged with an implant preloaded onto the tool 400. Thisarrangement can facilitate the use of the implant and also provide asterile implant and tool for an operation. Thus, the tool 400 can bedisposable after use in deploying the implant.

Referring again to FIG. 25, an embodiment of the tool 400 can alsocomprise an expansion indicator gauge 440 and a reset button 450. Theexpansion indicator gauge 440 can be configured to provide a visualindication corresponding to the expansion of the implant 200. Forexample, the gauge 440 can illustrate an exact height of the implant 200as it is expanded or the amount of expansion. As shown in FIG. 26, thetool 400 can comprise a centrally disposed slider element 452 that canbe in threaded engagement with a thread component 454 coupled to thedeployment portion 412.

In an embodiment, the slider element 452 and an internal cavity 456 ofthe tool can be configured such that the slider element 452 is providedonly translational movement in the longitudinal direction of the tool400. Accordingly, as the deployment portion 412 is rotated, the threadcomponent 454 is also rotated. In such an embodiment, as the threadcomponent 454 rotates and is in engagement with the slider component452, the slider element 452 can be incrementally moved from an initialposition within the cavity 456 in response to the rotation of thedeployment portion 412. An indicator 458 can thus be longitudinallymoved and viewed to allow the gauge 440 to visually indicate theexpansion and/or height of the implant 200. In such an embodiment, thegauge 440 can comprises a transparent window through which the indicator458 on the slider element 452 can be seen. In the illustratedembodiment, the indicator 458 can be a marking on an exterior surface ofthe slider element 452.

In embodiments where the tool 400 can be reused, the reset button 450can be utilized to zero out the gauge 440 to a pre-expansion setting. Insuch an embodiment, the slider element 452 can be spring-loaded, asshown with the spring 460 in FIG. 26. The reset button 450 can disengagethe slider element 452 and the thread component 454 to allow the sliderelement 452 to be forced back to the initial position.

The specific dimensions of any of the embodiment disclosed herein can bereadily varied depending upon the intended application, as will beapparent to those of skill in the art in view of the disclosure herein.Moreover, although the present inventions have been described in termsof certain preferred embodiments, other embodiments of the inventionsincluding variations in the number of parts, dimensions, configurationand materials will be apparent to those of skill in the art in view ofthe disclosure herein. In addition, all features discussed in connectionwith any one embodiment herein can be readily adapted for use in otherembodiments herein to form various combinations and sub-combinations.The use of different terms or reference numerals for similar features indifferent embodiments does not imply differences other than those whichmay be expressly set forth. Accordingly, the present inventions areintended to be described solely by reference to the appended claims, andnot limited to the preferred embodiments disclosed herein.

Referring now to FIG. 27, another embodiment of the implant isillustrated. FIG. 27 is a perspective view of an intervertebral implant300 in an expanded state. The implant 300 can have any of the featuresof implants described herein.

The implant 300 can comprise upper and lower body portions 302, 304,proximal and distal wedge members 306, 308, and an actuator shaft 310.In the unexpanded state, the upper and lower body portions 302, 304 canbe generally abutting with a height of the implant 300 being minimized.However, the implant 300 can be expanded, as shown in FIG. 27 toincrease the height of the implant 300 when implanted into theintervertebral space of the spine.

The implant 300 can be configured to include anti-torque structures 350.The anti-torque structures 350 can interact with at least a portion of abone graft inserter 500 during deployment of the implant 300 to ensurethat the implant 300 maintains its desired orientation. For example,when the implant 300 is being deployed and a rotational force is exertedon the actuator shaft 210, the anti-torque structures 350 can be engagedby the bone graft inserter 500 to maintain the rotational orientation ofthe implant 300 while the actuator shaft 310 is rotated. The anti-torquestructures 350 can comprise one or more slots on a side surface 370, 372on the proximal wedge member 306. The slots on a side surface 370, 372can be sized to accept a distal portion of the bone graft inserter 500.The anti-torque structures 350 can comprise one or more inwardlyextending holes or on the front surface 378 of the proximal wedge member306. The anti-torque structures 350 can include a pair of structures,such as a pair of indentations. In some embodiments, the anti-torquestructures 350 can also comprise one or more outwardly extendingstructures.

The anti-torque structures 350 can serve as the proximal engagementsection of the bone graft inserter 500, shown in FIGS. 28-31. Theanti-torque structures 350 can be used to engage a portion of the bonegraft inserter 500 for temporarily connecting the tool to the implant300. It is also contemplated that the anti-torque structures 350 canalso engage with the tool via a snap fit or press fit.

The implant 300 can be configured to include one or more channels 352 tofacilitate distribution of material within the implant 300 and/or withinthe intervertebral space. Each channel 352 can have one or more inlets.In the illustrated embodiment, the channel 352 has two inlets. Otherconfigurations are contemplated (e.g., one inlets per channel, twoinlets per channel, three inlets per channel, four inlets per channel,five inlets per channel, etc.). Each channel 352 can have one or moreoutlets. In the illustrated embodiment, each channel 352 has a pluralityof outlets (e.g., two outlets per channel, three outlets per channel,four outlets per channel, five outlets per channel, six outlets perchannel, seven outlets per channel, eight outlets per channel, nineoutlets per channel, ten outlets per channel, etc.). Otherconfigurations are contemplated (e.g., one outlet per channel). In theillustrated embodiment, the implant 300 has a single channel 352, withtwo inlets and eight outlets. The two inlets converge within the body ofthe implant 350. The eight outlets diverge within the body of theimplant 350.

In some embodiments, each anti-torque structure 350 can be associatedwith an inlet of the channel 352. In the illustrated embodiment, theimplant 300 includes two anti-torque structure 350 and two inlets. Onechannel 352 is shown, but other configurations are contemplated (e.g.,one channel, two channels, three channels, four channels, five channels,six channels, seven channels, eight channels, nine channels, more thantwo channels, more than three channels, more than four channels, aplurality of channels, etc.).

The channel 352 can extend from proximal wedge member 306 inward. Insome embodiments, the channel 352 extends entirely through the proximalwedge member 306. The channel 352 can have an inlet on the side surface370, 372 of the proximal wedge member 306. The channel 352 can have aninlet on the front surface 378 of the proximal wedge member 306. Thechannel 352 can have an inlet that spans between the side surface 370and the front surface 378 of the proximal wedge member 306. The channel352 can have an inlet that spans between the side surface 372 and thefront surface 378 of the proximal wedge member 306. The channel 352 canextend from an external surface of the proximal wedge member 306 towardan internal surface of the proximal wedge member 306.

The channel 352 can extend between upper and lower body portions 302,304. The channel 352 can extend along the actuator shaft 310. One ormore channels 352 can converge within the body of the implant 300. Insome embodiments, the channel 352 extends entirely through the distalwedge member 308. The channel 352 can have an outlet on a side surfaceand/or a front surface of the distal wedge member 308. In otherembodiments, the channel 352 extends through side surface 380, 382 ofthe implant 300. The side surface 380 can be the left side of theimplant 300 when viewed from the proximal end of the implant 300. In theillustrated embodiment, the channel 352 has a plurality of outlets oneach of the side surfaces 380, 382. Each outlet can diverge from otheroutlets within the body of the implant 300.

The channel 352 can have an outlet that spans between the side surfacesof the implant 300. The channel 352 can have an outlet that spansbetween the actuator shaft 310 and the side surfaces of the implant 300.In some embodiments, the channel 352 can extend from the proximal wedgemember 306 to the distal wedge member 308.

The inlets and/or outlets of the channel 352 can comprise a slot orother opening. The inlets and/or outlets of the channel 352 can comprisean inwardly extending hole. The inlets can be any size or shape todirect the flow inward. The outlets can be any size or shape todistribute the flow outward. The outlets can be oriented to evenlydistribute the material within the intervertebral space. The outlets canbe oriented to direct the flow of material toward gaps between theimplant 300 and the anatomy. The inlets can be associated with theanti-torque structure 350. For instance, a single aperture can serve thepurpose of an anti-torque structure 350 and an inlet for a channel 352.For instance, the distal portion of the bone graft inserter 500 cangrasp the implant 300 utilizing the anti-torque structures 350. The bonegraft inserter 500 can then deposit material into the inlet of thechannel 352, as described herein.

The implant 300 includes one or more channels 352 for packing with bonegraft or other bone-inducing-growth material to promote spinal fusion.The material can be bone graft or other osteoinductive, osteoconductivesubstance, or other osteogenic fusion graft material such as biologics.The material can be bone, healos, DBM, BMP, allograft, and autograft.The material can be bone morphogenic proteins, materials that restorescells, such as stem cells, or material that promotes cell growth. Thematerial inserted within the implant 300 can be one or more substances,such as antibiotics, chemotherapeutic substances, angiogenic growthfactors, substances for accelerating the healing of the wound, growthhormones, antithrombogenic agents, bone growth accelerators or agents,and the like. Indeed, various biologics can be used with the implant 300and can be inserted into the disc space or inserted along with theimplant 300. The channel 352 can facilitate circulation and bone growththroughout the intervertebral space and through the implant 300. In suchimplementations, the channel 352 can thereby allow bone growth throughthe implant 300 and integration of the implant 300 with the surroundingmaterials.

In some embodiments, the height of the implant 300 can be betweenapproximately 7-15 mm, and more preferably, between approximately 8-13mm. The width of the implant 300 can be between approximately 7-11 mm,and preferably approximately 9 mm. The length of the implant 200 can bebetween approximately 18-30 mm, and preferably approximately 22 mm.Thus, the implant 200 can have a preferred aspect ratio of betweenapproximately 7:11 and 15:7, and preferably approximately between 8:9and 13:9. It is contemplated that various modifications to the dimensiondisclosed herein can be made by one of skill and the mentioneddimensions shall not be construed as limiting.

The implant 300 can be made from any material, including non-metalmaterials such as plastics, PEEK™ polymers, and rubbers. Further, theimplant components can be made of combinations of PEEK™ polymers andmetals. The implant 300 can be formed from surgical metals includingtitanium. Accordingly, the implant 300 can be at least partiallyradiolucent, which radiolucency can allow a doctor to perceive thedegree of bone growth around and through the implant. The individualcomponents of the implant 300 can be fabricated of such materials basedon needed structural, biological and optical properties.

It is contemplated that the actuator shaft 310 can be rotated to causethe proximal and distal wedge members 306, 308 to move toward eachother, thus causing the upper and lower body portions 302, 304 to beseparated. Although, the present embodiment is illustrated using thismode of expansion, it is contemplated that other modes of expansiondescribed above (e.g., one way-ratchet type mechanism) can be combinedwith or interchanged herewith.

In some embodiments, the implant 300 can be configured such that theproximal and distal wedge members 306, 308 are interlinked with theupper and lower body portions 302, 304 to improve the stability andalignment of the implant 300. For example, the upper and lower bodyportions 302, 304 can be configured to include slots (similar to slot220 shown in FIG. 16A, and slots 220, 222 shown in FIG. 16B, see alsoslot 322 in FIG. 27). In such an embodiment, the proximal and distalwedge members 306, 308 can be configured to include at least one guidemember (similar to an upper guide member 230 of the proximal wedgemember 206 shown in FIG. 16A and an upper guide member 232 of the distalwedge member 208 shown in FIG. 18) that at least partially extends intoa respective slot of the upper and lower body portions 302, 304. Thearrangement of the slots and the guide members can enhance thestructural stability and alignment of the implant 300.

In some embodiments, the slots and guide members can be configured toincorporate a generally dovetail shape. Thus, once a given guide memberis slid into engagement with a slot, the guide member can only slidelongitudinally within the slot and not vertically from the slot. Thisarrangement can ensure that the proximal and distal wedge members 306,308 are securely engaged with the upper and lower body portions 302,304.

FIG. 27 illustrates the angular relationship of the proximal and distalwedge members 306, 308 and the upper and lower body portions 302, 304.As mentioned above, the dovetail shape of the slots and guide membersensures that for each given slot and guide member, a given wedge memberis generally interlocked with the give slot to only provide one degreeof freedom of movement of the guide member, and thus the wedge member,in the longitudinal direction of the given slot. Accordingly, in such anembodiment, the wedge members 306, 308 may not be separable from theimplant when the implant 300 is in the unexpanded state due to thegeometric constraints of the angular orientation of the slots and guidemembers with the actuator shaft inhibiting longitudinal relativemovement of the wedge members 306, 308 relative to the upper and lowerbody portions 302, 304. Such a configuration ensures that the implant300 is stable and structurally sound when in the unexpanded state orduring expansion thereof, thus facilitating insertion and deployment ofthe implant 300.

In addition, it is contemplated that some embodiments of the implant 300can be configured such that the upper and lower body portions 302, 304each include side portions (similar to upper side portion 240 of theupper body portion 202 shown in FIG. 16B and lower side portion 242 ofthe lower body portion 204 shown in FIG. 17, see all side portion 340 inFIG. 27) that project therefrom and facilitate the alignment,interconnection, and stability of the components of the implant 300. Theupper and lower side portions can be configured to have complementarystructures that enable the upper and lower body portions 302, 304 tomove in a vertical direction. Further, the complementary structures canensure that the proximal ends of the upper and lower body portions 302,304 generally maintain spacing equal to that of the distal ends of theupper and lower body portions 302, 304. The complementary structures canalso include motion limiting portions that prevent expansion of theimplant 300 beyond a certain height. This feature can also tend toensure that the implant 300 is stable and does not disassemble duringuse. The upper and lower side portions can each include complementarystructures to facilitate the alignment, interconnection, and stabilityof the components of the implant 300. Having a pair of each of upper andlower side portions can ensure that the upper and lower body portions302, 304 do not translate relative to each other, thus further ensuringthe stability of the implant 300.

In some embodiments, the actuator shaft 310 can facilitate expansion ofthe implant 300 through rotation, longitudinal contract of the pin, orother mechanisms. The actuator shaft 310 can include threads thatthreadably engage at least one of the proximal and distal wedge members306, 308. The actuator shaft 210 can also facilitate expansion throughlongitudinal contraction of the actuator shaft, which in turn moves theproximal and distal wedge members 306, 308 closer together. It iscontemplated that in other embodiments, at least a portion of theactuator shaft can be axially fixed relative to one of the proximal anddistal wedge members 306, 308 with the actuator shaft being operative tomove the other one of the proximal and distal wedge members 306, 308.

Further, in embodiments wherein the actuator shaft 310 is threaded, itis contemplated that the actuator shaft 310 can be configured to bringthe proximal and distal wedge members closer 306, 308 together atdifferent rates. In such embodiments, the implant 300 could be expandedto a V-configuration or wedged shape. For example, the actuator shaft310 can comprise a variable pitch thread that causes longitudinaladvancement of the distal and proximal wedge members 306, 308 atdifferent rates. The advancement of one of the wedge members at a fasterrate than the other could cause one end of the implant 300 to expandmore rapidly and therefore have a different height that the other end.Such a configuration can be advantageous depending on the intervertebralgeometry and circumstantial needs.

FIG. 28 is a view of an actuator shaft 310 of the implant 300. In thisembodiment, the actuator shaft 310 can be a single, continuous componenthaving threads 394 disposed thereon for engaging the proximal and distalwedge members 306, 308. The threads can be configured to be left handthreads at a distal end of the actuator shaft 310 and right hand threadsat a proximal other end of the actuator shaft 310 for engaging therespective ones of the distal and proximal wedge members 308, 306.Accordingly, upon rotation of the actuator shaft 310, the wedge members306, 308 can be caused to move toward or away from each other tofacilitate expansion or contraction of the implant 300. It is alsocontemplated that relative movement of the wedge members 306, 308 can beachieved through the use of the other actuator shaft 30 describedherein.

In accordance with an embodiment, the actuator shaft 310 can alsocomprise a tool engagement section 396. The tool engagement section 396can be configured to be engaged by a tool. The tool engagement section396 can be shaped as a polygon, such as a hex shape. The tool engagementsection 396 can be star shaped and include six points, which facilitatesthe transfer of torque to the actuator shaft 310 from the tool. Othershapes and configurations can also be used.

The implant 300 can comprise one or more protrusions on a bottom surfaceof the lower body portion 304. The upper body portion 302 can alsodefine a top surface having one or more protrusions thereon. Theprotrusions can allow the implant 300 to engage the adjacent vertebraewhen the implant 300 is expanded to ensure that the implant 300maintains a desired position in the intervertebral space. Theprotrusions can be configured in various patterns. As shown, theprotrusions can be formed from grooves extending widthwise along thebottom surface of the implant 300. The protrusions can becomeincreasingly narrow and pointed toward their apex. However, it iscontemplated that the protrusions can be one or more raised points,cross-wise ridges, or the like. The implant 300 can define generallyconvex top and bottom surfaces. This shape can be configured togenerally match the concavity of adjacent vertebral bodies.

FIGS. 28-31 illustrate cross-sectional views of the lower body portion304 of the implant 300, according to an embodiment. These figuresprovide additional clarity as to the configuration of the one or morechannels 352. Additionally, the upper and lower body portions 302, 304can also define a central receptacle 390 wherein the actuator shaft 310can be received. Further, as mentioned above, the upper and lower bodyportions 302, 304 can define one or more anti-torque structures 350.

FIGS. 28-31 illustrate views of the proximal wedge member 306 of theimplant 300. As described above, the proximal wedge member 306 caninclude one or more anti-torque structures 350. The proximal wedgemember 306 can comprise a central aperture 374 where an actuator shaft310 can be received. When actuator shaft 310 is used in an embodiment,the central aperture 374 can be threaded to correspond to the threads394 of the actuator shaft 310. In other embodiments, the actuator shaft310 can engage other portions of the wedge member 306 for causingexpansion or contraction thereof

FIGS. 28-31 illustrate views of the distal wedge member 308 of theimplant 300. The central aperture 376 can be configured to receive anactuator shaft 310 therethrough. When actuator shaft 310 is used in anembodiment, the central aperture 376 can be threaded to correspond tothe threads 394 of the actuator shaft 310. In other embodiments, theactuator shaft 310 can engage other portions of the wedge member 308 forcausing expansion or contraction thereof

FIGS. 28-31 illustrate views of the bone graft inserter 500. The bonegraft inserter 500 can comprise a handle section (not shown) and adistal engagement section 504. The handle section can be configured tobe held by a user and can comprise various features to facilitateimplantation and deployment of the implant 300.

The bone graft inserter 500 can be sized to accept one or more toolstherethrough. The bone graft inserter 500 can comprise a central lumenor bore. The bone graft inserter 500 can include one or more rotatabletools therethrough, such as a rotatable deployment tool. The bone graftinserter 500 can include tethering portion. In such an embodiment, thetethering portion can be used to attach the implant 300 to the bonegraft inserter 500 prior to insertion and deployment. The deploymenttool can be used to actuate the implant 300 and rotate the actuatorshaft 310 thereof for expanding the implant 300.

Then, after the implant 300 is expanded and properly placed, thetethering portion can again be used to untether or decouple the implant300 from the bone graft inserter 500.

In some embodiments, the tethering portion can be the distal engagementsection 504 of the bone graft inserter 500. The distal engagementsection 504 can comprise an anti-torque component 522. As describedabove, in an embodiment, the implant 300 can comprise one or moreanti-torque structures 350. The anti-torque component 522 can compriseone or more protrusions that engage the anti-torque structures 350 toprevent movement of the implant 300 when a rotational force is appliedto the actuator shaft 210 via the rotatable deployment tool. Asillustrated, the anti-torque component 522 can comprise a pair of pinsor fingers that extend from a distal end of the bone graft inserter 500.However, it is contemplated that the implant 300 and bone graft inserter500 can be variously configured such that the anti-torque structures 350and the anti-torque component 522 interconnect to prevent a torque beingtransferred to the implant 300. The generation of the rotational forcewill be explained in greater detail below with reference to FIG. 28,which is a cross sectional view of the bone graft inserter 500illustrating the interrelationship of the components of the implant 300and the distal engagement section 504. In some embodiments, thetethering portion is actuated to grasp the implant 300. In otherembodiments, the tethering portion is a snap fit or other friction fit.

The deployment tools and the tethering portion can move independently ofeach other and independently of the fixed portions of the bone graftinserter 500. Thus, while holding the bone graft inserter 500, thedeployment tools and the tethering portion can be moved to selectivelyexpand or contract the implant 300 or to attach the implant 300 to thebone graft inserter 500, respectively. In some embodiments, thedeployment tools can be rotated to cause rotation of an actuator shaft310 of an implant 300 engaged with the bone graft inserter 500. In someembodiments, the tethering portion can be rotated to cause grasping ofan implant 300.

The deployment tool (not shown) comprise a distal engagement memberconfigured to engage a proximal end 396 of the actuator shaft 310 of theimplant 300. The deployment tool is configured for rotating the actuatorshaft 310 to thereby expand the implant 300 from an unexpanded state toand expanded state. In some embodiments, the deployment tool can beconfigured with a threaded distal section that can be threadably coupledto an interior threaded portion of the actuator shaft 310.

In some embodiments, the bone graft inserter 500 and/or the deploymenttool can be prepared for a single-use and can be packaged with animplant 300 preloaded onto the bone graft inserter 500. This arrangementcan facilitate the use of the implant 300 and also provide a sterileimplant 300 and bone graft inserter 500 for an operation. Thus, the bonegraft inserter 500 can be disposable after use in deploying the implant300. In some embodiments, the bone graft inserter 500 can be packagedwith the implant 300 preloaded on the distal engagement section 504. Inother embodiments, the bone graft inserter 500 and the implant 300 canbe packaged and/or sold separately.

In some methods of use, the surgeon can remove disc material between twoadjacent vertebrae. The implant 300 can be introduced into the spinethrough a posterior, posterolateral, lateral or anterior approach. Theimplant 300 can be utilized in any area of the spine including cervical,thoracic and lumbar areas of the spine.

The implant 300 can be expanded to fit within the intervertebral discspace. The implant 300 can be inserted, expanded, and filled withoutremoving the bone graft inserter 500. In some methods of use, theimplant 300 is inserted through a minimally invasive approach to thespine. Once expanded, the implant 300 has additional gaps within theimplant 300. Once expanded, the implant 300 can be filled with materialin situ. The ability to introduce material within the implant 300 afterthe implant 300 is expanded decreases voids between the implant 300 andthe anatomy. The material reduces the dead space of the expanded implant300. As the implant 300 is expanded in situ, the expansion results inincreased heights, as well as increased dead space within the implant300. The expansion provides more space to place material within theimplant 300. The outlets can direct the flow of material toward theanatomy such as the endplates of the vertebrae. The ability to directand/or control the flow of material into dead spaces may improve spinalfusion.

The bone graft inserter 500 can include a hollow cannula or tube. Thebone graft inserter 500 can accept one or more tools. The bone graftinserter 500 can accept a deployment tool to rotate the actuator shaft310. The bone graft inserter 500 can include the handle portion at oneend and the distal engagement section 504 at the opposing end. Thedistal engagement section 504 can allow a flush engagement between thedistal engagement section 504 and the implant 300. In some embodiments,the distal engagement section 504 engages the anti-torque features 250to prevent rotation of the implant 300 during actuation of the actuatorshaft 310. The deployment tool can be a screwdriver (e.g., hex, allen,Phillips, star, etc.) designed to engage the actuator shaft 310. Thedeployment tool is rotated within the bone graft inserter 500 to rotatethe actuator shaft 310 and expand the implant 300. The acutor shaft 310rotates within the implant 300 to move one or more of the distal andproximal wedges 306, 308 toward each other. The deployment tool canextend through the handle portion of the bone graft inserter 500 toallow independent actuation of the actuator shaft 310. The deploymenttool can be rotated by hand or by tool.

In some embodiments, the deployment tool can be removed from the bonegraft inserter 500 once the implant 300 is expanded. In otherembodiments, the deployment tool remains within the bone graft inserter500 during the movement of material. In some embodiments, the materialis passed through the bone graft inserter 500 after the implant 300 isexpanded. In some embodiments, the material is loaded within the bonegraft inserter 500 prior to insertion of the implant 300. In someembodiments, the material is loaded within the bone graft inserter 500after insertion of the implant 300 prior to expansion of the implant300. In some embodiments, the material is loaded within the bone graftinserter 500 after expansion of the implant 300. The material can beloaded at any step of the surgical procedure.

The bone graft inserter 500 can include a plunger 502 or other device toexpel the material from the bone graft inserter 500. The plunger 502 canform a portion of a syringe. The plunger 502 can move the material fromwithin the bone graft inserter 500 toward the inlets of the channel 352.In some embodiments, the bone graft inserter 500 includes a path 354 foreach inlet. In the illustrated embodiment, the implant 300 includes twoinlets. The bone graft inserter 500 can include two paths 354 that alignwith the two inlets. The material is inserted along the paths 354 andinto the inlets of the channel 352. The material can be selected basedupon the needs of the surgeon. The material enters the implant 300through the proximal wedge 306 of the implant 300. The inlet of thechannel 352 allows the material to flow through the proximal wedgetoward the dead space within the expanded implant 300. The channel 352allows the material to flow between the proximal wedge 306 and thedistal wedge 308. The material can be directed toward one or moreoutlets. The outlets can be located on any surface of the implant 300.

The implant 300 can be sufficiently filled with material. The materialcan fill one or more voids within the body of the implant 300. Thematerial can fill one or more voids between the implant 300 and theanatomy such as the endplates of the vertebrae. The implant 300 can beoverfilled such that material flows from the inlets and/or outlets ofthe channel 352. The material can be metered based upon the implant 300in use. The material can be preloaded based upon the implant 300 in use.The surgeon can utilize all of the material that is metered and/orpreloaded. In other methods of use, the surgeon is provided with excessmaterial. The surgeon can determine the quantity of material to use as aportion of the material provided.

The method allows for spinal fusion to be simplified. There is no needto remove the bone graft inserter 500 at any point during the surgery.The bone graft inserter 500 facilitates placement of the implant 300within the intervertebral space. The bone graft inserter 500 preventsrotation of the implant 300 when the actuator shaft 310 is rotated. Thebone graft inserter 500 remains in place as the implant 300 is expanded.The bone graft inserter 500 facilitates the flow of material to thechannel 352 of the implant 300. The bone graft inserter 500 can includeone or more paths 354 that align with one or more inlets of the channel352. The bone graft inserter 500 remains in place through insertion,expansion, and depositing of the material within the expanded implant300.

The path of the material through the expanded implant 300 can be known.The one or more channels 352 can be prefabricated. The dimensions of theexpanded implant 300 can be known. Therefore, the amount of material tofill the implant 300 can be determined. The bone graft inserter 500 canbe preloaded with this amount of material. In other embodiments, thesurgeon inserts the material through the bone graft inserter 500 basedon his judgement or other cues during surgery. The outlets of thechannel 352 direct the flow of materials. The outlets can be placed atanatomically significant locations to impact the flow of material. Insome embodiments, the size of the outlet can be enlarged to allow morematerial to flow to a certain location. The size, shape, or othercharacteristic of the outlets can be manufactured to influence the flowof material.

The dead space created by expanding the implant can be filled withmaterial in situ. Static implants, e.g., those that are not expanded,can be preloaded with material. The shape of the implant does notchange. The amount of dead space within the implant does not change. Incontrast, the dead space does change with expandable implants. Theimplant 300 cannot be preloaded with material to fill the entire deadspace. In some methods of use, the implant 300 is inserted within theintervertebral space without first injecting material into the implant.In some methods of use, the implant 300 is inserted within theintervertebral space without first injecting material into theintervertebral space.

The bone graft inserter 500 is configured as an insertion tool to placethe implant 300. The bone graft inserter 500 can include one or morefeatures for grasping and moving the implant 300. The bone graftinserter 500 can include a lumen for the passage of one or more tools.The actuator shaft 310 of the implant 300 is accessed and rotated by theone or more tools inserted through the bone graft inserter 500. The bonegraft inserter 500 includes one or more paths 354 which permit thematerial to flow from the bone graft inserter 500 toward the implant300. The material flows from the bone graft inserter 500 into theinterior of the expanded implant 300.

The bone graft inserter 500 facilitates the distribution of materialwithin the disc space. FIGS. 28-31 show the central lumen of the bonegraft inserter 500. The central lumen can be open toward the implant300. The proximal wedge 306 can deflect the material toward the path354. In other embodiments, the central bore is not open toward theimplant. The one or paths 354 can be enclosed within the bone graftinserter 500. The material can be placed in the central bore before theimplant 300 is inserted. The material can be place in the central borebefore the implant 300 is expanded. The material can be placed in thecentral bore after the implant 300 is expanded. A device such as theplunger 502 can be used to push the material down the central bore. Whenthe material hit the end of the bone graft inserter 500 and/or theproximal wedge 306, the material can be diverted to the one or morepaths 354. The one or more paths 354 can direct the material toward oneor more channels 352 within the implant 300. The shape and size of thechannel 352 within the implant can distribute the material on one ormore sides of the implant 300. The material can partially or entirelyfill the disc space. The bone graft inserter 500 can include one or morepaths 354 that lead to one or more inlets.

The one or more channels 352 within the implant 300 facilitates thedistribution to any side of the implant 300 (e.g., top, bottom, left,right, proximal wedge front surface, distal wedge back surface, etc.).The one or more channels 352 facilitate the distribution of materialwithin the implant 300. The outlets facilitates the distribution ofmaterial to the disc space. The outlets are provided within the externalsurface of the implant 300 to distribute material to the external spacearound the implant 300.

As discussed herein, the material can be introduced through the bonegraft inserter 500. In other embodiments, the material is preloadedwithin the bone graft inserter 500 prior to surgery or a surgical stepdescribed herein. The bone graft inserter 500 can be mounted to theimplant 300. The bone graft inserter 500 can clasp onto the implant 300and prevent rotation of the implant 300 relative to the bone graftinserter 500. The bone graft inserter 500 allows the surgeon to positionthe implant 300 within the disc space. The material can be pushed with aplunger of the bone graft inserter 500. The material can be urgedthrough paths 354 in the bone graft inserter 500 which align with theinlets of the channel 352. The material is inserted into the disc spacethrough the one or more channels 352. The one or more channels extendfrom one or more inlets to one or more outlets distributed on theimplant 300. The material is spread out through the implant 300 via thechannel 352. The material is spread out through outlets in the channel352. The material will exit the implant 300 via the outlets and providea distribution of the material within the disc space. The channel 352can be designed to enhance or alter the distribution of material suchthat more or less material can be directed toward certain outlets. Thegoal is to enhance vertebral fusion by the distribution of materialwithin the disc space.

Once the material has been dispelled by the bone graft inserter 500, thebone graft inserter 500 can be removed. The implant 300 and thedispelled material remain within the disc space to facilitate fusion.

FIGS. 28-31 are cross-section view of the bone graft inserter 500 andthe implant 300. The bone graft inserter 500 can be used for positioningthe implant 300 and delivering material to the disc space once theimplant 300 is positioned and expanded. The bone graft inserter 500 caninclude a cylindrical body portion having a central lumen. The bonegraft inserter 500 can include the handle portion (not shown). The bonegraft inserter 500 can include the distal engagement section 504. Thedistal engagement section 504 can extend from the cylindrical bodyportion. The distal engagement section 504 can grasp the implant 300 asdescribed herein. For instance, the distal engagement section 504 caninclude one or more anti-torque component 522. The anti-torque component522 can conform to the proximal wedge 306 of the implant 300. The distalengagement section 504 can securely hold the implant 300. The distalengagement section 504 can be coupled with the anti-rotation feature 350of the implant 300. When the implant 300 is coupled to the bone graftinserter 500, the bone graft inserter 500 can be used to insert theimplant 300 within the disc space. The procedure can be minimallyinvasive. Once the implant 300 is positioned within the space, theimplant 300 can be expanded. The surgeon will rotate the actuator shaft310 to expand the implant 300. FIGS. 28-31 show the expanded implant300. The expansion of the implant 300 can restore the disc space height.

Once the implant 300 is positioned and expanded, the material can beforced toward the implant 300. The material can be forced down the ofthe body portion of the bone graft inserter 500. The material can beforce down paths 354 of the bone graft inserter 500. The material isforced from the bone graft inserter 500 into the one or more channels352 of the implant.

What is claimed is:
 1. An assembly comprising: an expandable implantcomprising upper and lower body portions, an actuator shaft receivedbetween the upper and lower body portions, a proximal wedge member and adistal wedge member coupled to the actuator shaft, and a channelextending from the proximal wedge member through the expandable implant,wherein rotation of the actuator shaft causes movement of one or more ofthe proximal wedge member and the distal wedge member; a tool configuredto engage a portion of the expandable implant for placement within theintervertebral space, the tool comprising a central lumen incommunication with the channel configured to direct material from thetool toward the channel, wherein the tool remains in place duringinsertion of the implant, expansion of the implant, and movement of thematerial toward the channel.
 2. The assembly of claim 1 wherein thechannel comprises two or more inlets.
 3. The assembly of claim 1 whereinthe channel comprises two or more outlet.
 4. The assembly of claim 1wherein the tool comprises one or more paths for the material.
 5. Theassembly of claim 4 wherein the number of paths corresponds with thenumber of inlets.
 6. The assembly of claim 1 further comprising aplunger to expel material from the tool.
 7. The assembly of claim 1further comprising a deployment tool to rotate the actuator shaft. 8.The assembly of claim 1 further comprising one or more anti-rotationfeatures associated with the tool and the implant.
 9. A methodcomprising: coupling an implant with a tool; positioning the implantbetween adjacent vertebrae with the tool, the implant comprising upperand lower body portions, an actuator shaft received between the upperand lower body portions, a proximal wedge member and a distal wedgemember coupled to the actuator shaft, and a channel extending from theproximal wedge member through the expandable implant; rotating theactuator shaft to expand the implant while the implant is coupled to thetool; directing material from the tool toward the implant while theimplant is coupled to the tool; and decoupling the implant with thetool.
 10. The method of claim 9 further comprising directing materialthrough a channel in the implant.
 11. The method of claim 9 furthercomprising directing material through a path in the tool.
 12. The methodof claim 9 further comprising utilizing a plunger to direct thematerial.
 13. The method of claim 9 wherein the material is bone graft.14. The method of claim 9 further comprising directing material throughan inlet in the proximal wedge.
 15. The method of claim 9 furthercomprising directing material through a plurality of outlets.
 16. Themethod of claim 9 further comprising preloading the material in the toolprior to coupling the implant with the tool.
 17. The method of claim 9further comprising loading the material in the tool after rotating theactuator shaft to expand the implant.
 18. An assembly comprising: anexpandable implant comprising upper and lower body portions configuredto be moved apart to expand the expandable implant, and a channelextending at least from an outside surface of the expandable implant toan inside surface of the expandable implant; a tool configured to engagethe expandable implant for placement within the intervertebral space,the tool comprising a central lumen in communication with the channelconfigured to direct material from the tool toward the channel andtoward the inside surface of the expandable implant, wherein the toolremains in place during insertion of the implant, expansion of theimplant, and movement of the material toward the channel.
 19. Theassembly of claim 18 wherein the channel comprises two or more inlets.20. The assembly of claim 18 wherein the channel comprises two or moreoutlet.
 21. The assembly of claim 18 wherein the tool comprises one ormore paths for the material.
 22. The assembly of claim 21 wherein thenumber of paths corresponds with the number of inlets.
 23. The assemblyof claim 18 further comprising a plunger to expel material from thetool.
 24. The assembly of claim 18 further comprising one or moreanti-rotation features associated with the tool and the expandableimplant.
 25. A method comprising: coupling an implant with a tool;positioning the implant between adjacent vertebrae with the tool;expanding the implant while the implant is coupled with the tool;directing material from the tool toward a channel in the implant whilethe implant is coupled to the tool; and decoupling the implant with thetool.
 26. The method of claim 25 further comprising directing materialthrough the channel in the implant.
 27. The method of claim 25 furthercomprising directing material through a path in the tool.
 28. The methodof claim 25 further comprising utilizing a plunger to direct thematerial.
 29. The method of claim 25 wherein the material is bone graft.30. The method of claim 25 further comprising directing material througha plurality of outlets.
 31. The method of claim 25 further comprisingpreloading the material in the tool prior to coupling the implant withthe tool.